GEOGRAPHIC INFORMATION SYSTEMS AS AN ICT IN AGRICULTURE

INTRODUCTION TO GEOGRAPHIC INFORMATION SYSTEMS (GIS)

A geographic information system is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data. In a general sense, the term describes any information system that integrates, stores, edits, analyzes, shares and displays geographic information for informing decision making. GIS is a specific ICT system of hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modelling and display of spatially-referenced data for solving, planning and management problems in almost any field- agriculture, statistics, surveying, geology, geography, cartography, resource management, database technology, etc. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data, maps, and present the results of all these operations. Hence, a GIS developed for an application, jurisdiction, enterprise or purpose may not be necessarily interoperable or compatible with a GIS that has been developed for some other application, jurisdiction, enterprise, or purpose. What goes beyond a GIS is a spatial data infrastructure (SDI), a concept that has no such restrictive boundaries. Geographic information science is the science underlying the geographic concepts, applications and systems. The GIS can be used to handle a broader range of data as comparable to any other isolated ICT system for both spatial and non-spatial data alone.

Up to this point, the discussion has focused on describing how GPS determines a location on the surface of the Earth. Now the discussion can shift to the process of describing what is at the location. The "what" is the object or objects which will be mapped. These objects are referred to as "Features", and are used to build a GIS. It is the power of GPS to precisely locate these Features which adds so much to the utility of the GIS system. On the other hand, without Feature data, a coordinate location is of little value.

Feature Types

There are three types of Feature which can be mapped: Points, Lines and Areas. A Point Feature is a single GPS coordinate position which is identified with a specific Object. A Line Feature is a collection of GPS positions which are identified with the same Object and linked together to form a line. An Area Feature is very similar to a Line Feature, except that the ends of the line are tied to each other to form a closed area.
A GIS can be used to emphasize the spatial relationships among the objects being mapped. While a computer-aided mapping system may represent a road simply as a line, a GIS may also recognize that road as the boundary between wetland and urban development between two census statistical areas.

Describing Features

As stated above, a Feature is the object which will be mapped by the GPS system. The ability to describe a Feature in terms of a multi-layered database is essential for successful integration with any GIS system. For example, it is possible to map the location of each house on a city block and simply label each coordinate position as a house. However, the addition of information such as color, size, cost, occupants, etc. will provide the ability to sort and classify the houses by these catagories.

These catagories of descriptions for a Feature are know as Attributes. Attributes can be thought of as questions which are asked about the Feature. Using the example above, the Attributes of the Feature "house" would be "color", "size", "cost" and "occupants".

Logically, each question asked by the Attributes must have an answer. The answers to the questions posed by the Attributes are called Values. In the example above, an appropriate Value (answer) for the Attribute (question) "color" may be "blue".

The following table illustrates the relationship between Features, Attributes and Values: Eg

Feature            Attribute         Value

House  Color               Blue

            Size                 3 BDR

            Cost                 $118K

            Occupants       5

By collecting the same type of data for each house which is mapped, a database is created. Tying this database to position information is the core philosophy underlying any GIS system.

Feature Lists

The field data entry process can be streamlined by the use of a Feature List. The Feature List is a database which contains a listing of the Features which will be mapped, as well as the associated Attributes for each Feature. In addition, the Feature List contains a selection of appropriate Values for each Attribute. The Feature List can be created on the CMT hand-held GPS data collector, or on a PC.

When a Feature List is used in the field, the first step is to select the Feature to be mapped. Once a Feature is selected, the Attributes for that Feature are automatically listed. A Value for each Attribute can then be selected from the displayed list of predetermined Values.

The use of a Feature List streamlines the data entry process and also ensures consistent data entry among different users in the same organization.

Exporting to a GIS System

Data capture—putting the information into the system—involves identifying the objects on the map, their absolute location on the Earth's surface, and their spatial relationships. Software tools that automatically extract features from satellite images or aerial photographs are gradually replacing what has traditionally been a time-consuming capture process. Objects are identified in a series of attribute tables—the "information" part of a GIS. Spatial relationships, such as whether features intersect or whether they are adjacent, are the key to all GIS-based analysis.
The final step in incorporating GPS data with a GIS system is to export the GPS and Feature data into the GIS system. During this process, a GIS "layer" is created for each Feature in the GPS job. For example, the process of exporting a GPS job which contains data for House, Road and Lot Features would create a House layer, a Road layer and a Lot layer in the GIS system. These layers can then be incorporated with existing GIS data.

Once the GPS job has been exported, the full power of the GIS system can be used to classify and evaluate the data.A GIS makes it possible to link, or integrate, information that is difficult to associate through any other means. Thus, a GIS can use combinations of mapped variables to build and analyze new variables.

The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. Most of the information we have about our world contains a location reference, placing that information at some point on the globe. When rainfall information is collected, it is important to know where the rainfall is located. This is done by using a location reference system, such as longitude and latitude, and perhaps elevation. Comparing the rainfall information with other information, such as the location of marshes across the landscape, may show that certain marshes receive little rainfall. This fact may indicate that these marshes are likely to dry up, and this inference can help us make the most appropriate decisions about how humans should interact with the marsh. A GIS, therefore, can reveal important new information that leads to better decision making.

Since much of the information in a GIS comes from existing maps, a GIS uses the processing power of the computer to transform digital information, gathered from sources with different projections, to a common projection. The way maps and other data have been stored or filed as layers of information in a GIS makes it possible to perform complex analyses.

DIFFERENTIATING BETWEEN GIS AND THE GPS

The electronics revolution of the last several decades has spawned two technologies that will impact agriculture in the next decade. These technologies are Geographic Information Systems (GIS) and Global Positioning System (GPS). Along with GIS and GPS there have appeared a wide range of sensors, monitors and controllers for agricultural equipment such as shaft monitors, pressure transducers and servo motors. Together they will enable farmers to use electronic guidance aids to direct equipment movements more accurately, provide precise positioning for all equipment actions and chemical applications and, analyze all of that data in association with other sources of data (agronomic, climatic, etc). This will add up to a new and powerful toolbox of management tools for the progressive farm manager.

Precision farming, a farming management concept based on observing and responding to intra-field variations, does not "happen" as soon as one purchases a GPS unit or yield monitor. It occurs over time as a farmer adopts a new level of management intensity on the farm. Implicit in this is an increased level of knowledge of the precision farming technologies such as GPS. What is perhaps more important for the success of precision farming, at least initially, is the increased knowledge that a farmer needs of his natural resources in the field. This includes a better understanding of soil types, hydrology, microclimates and aerial photography. A farmer should identify the variance of factors within the fields that effect crop yield before a yield map is acquired. A yield map should serve as verification data to quantify the consequences of the variation that exists in a field. Management strategies and prescription map development will likely rely on sources other than yield maps. The one important key source of data a farmer should not start precision farming without is an aerial photograph.

The development of Precision agriculture and its implementation of precision has been made possible by combining the Global Positioning System (GPS) and geographic information systems (GIS). These technologies enable the coupling of real-time data collection with accurate position information, leading to the efficient manipulation and analysis of large amounts of geospatial data. Let us differentiate between the 2…

GIS (Geographic Information Systems) is tool to display and analyze information geographically. GPS (Global Positioning Systems) is a technology that uses satellites to give one its position on the Earth with the aid of a GPS device or unit. GPS can be incorporated into GIS by using a GPS device to collect points, lines, or polygons, which can be imported into a GIS application for future analysis and interpretation. As a start, GPS is one of the ways to precisely pinpoint specific locations in almost any place on the planet. Simply, it is a network of satellites that determines specific coordinates on earth (I will not dwell much on this as I have already covered exhaustively GPS and all its uses in my previous blog). GIS (Geographic Information System) is an integrated collection of computer software and data is used to view and manage information about geographic places, analyze spatial relationships, and model spatial processes. A GIS provides a framework for gathering and organizing spatial data and related information so that it can be displayed and analyzed.

GIS is frequently confused with GPS because it is a more generic acronym (Geographic Information System) used to describe a more complex mapping technology that is connected to a particular database. Because it’s generic, it is a broader term than the GPS in its technical sense. Thus, GIS is a computer program or application that is utilized to view and handle data about geographic locations and spatial correlations among others. It simply gives the user a framework to obtain information.

The GIS being a tool to display and analyze information geographically and the GPS being a technology that uses satellites to collect information with the aid of a GPS device or unit. GPS can then be incorporated into GIS by using a GPS device to collect points, lines, or polygons, which can be imported into a GIS application for future analysis and interpretation. Once collected, by GPS or any other method, spatial data would then probably land in spatially enabled database where they could be managed, accessed and analysed by GIS: by, for instance, adding topology, connectivity and driving directions for the roundabout or calculating time and distance of animal migration.GIS is the implementation of database for spatial data. If a database can have text, numbers, dates, and photos, it can have maps as well. It's not just about the location, it's about querying the location and analyzing that location with respect to other locations. It's just like querying and analyzing tabular data. The only difference is that if a picture is worth a thousand words, a map is worth a thousand pictures.

GIS is a mix of science (Geography), information systems, and modern software technologies

Where to from here?

There is no doubt that precision agriculture is not yet a mature concept. The technologies, impressive as they are, still require some development. More development is required in the areas of agronomic application of the vast amounts of data obtained. In the future more research will be required to obtain the full benefits of the technology. More training will be required as well, to enable us to use the technology. Unfortunately, we can expect to make some mistakes along the way. Nothing that promises as much as precision agriculture will come easily, but eventually we can expect it to provide us with the one benefit which justifies its use--profits. Hopefully they will emerge sooner, rather than later.

GPS APPLICATIONS IN AGRICULTURE, CONT'D

1. Equipment/Tractor Guidance Systems

Farmers cannot put their tractors on auto-pilot. If they plough their fields with a recording GPS system the tractor can then be programmed to follow the same route - for cultivating, fertilizing, pest control and harvesting. The programming of tractor routes has the potential to save a lot of money. Several manufacturers are currently producing guidance systems using high precision DGPS that can accurately position a moving vehicle within a foot or less. These guidance systems may replace conventional equipment markers for spraying or seeding and may be a valuable field scouting tool. 

Lightbar-guided and automated steering systems help maintain precise swath-to-swath widths. Guidance systems identify an imaginary A-B starting line, curve or circle for parallel swathing using GPS positions and a control module. The module takes into account the swath width of the implement and then uses GPS to guide machines along parallel, curved, or circular evenly spaced swaths. Guidance systems include a display module that uses audible tones or lights as directional indicators for the operator. The guidance system allows the operator to monitor the lightbar to maintain the desired distance from the previous swath.

Guidance systems require two principle components: a light bar or screen, which is essentially an electronic display showing a machine's deviation from the intended position, and a GPS receiver for locating the position. This receiver must be designed for this purpose and it must operate at a higher frequency (position calculations are usually 5 to 10 times per second) than a GPS receiver designed to record positions for a yield monitor. GPS receivers designed for guidance can be used in conjunction with a yield monitor or for other positioning equipment.

Automated steering systems integrate GPS guidance capabilities into the vehicle steering system. Automated steering frees the operator from steering the equipment except at corners and at the ends of fields.

An Example of Swath guided GPS system

• ·         Anchor points established to create base line on map screen.
• ·         Parallel lines generated at desired swath spacing.
• ·         Can be used for straight or contour swaths
• ·         Light bar or similar device used to provide guidance along line.
• Automatic steering possible.

2. Yield Monitoring Systems

Estimates of yield variations across a property can be made using GPS. To do this the property is divided into zones and the yield of each zone is estimated and plotted on a map. The map can then be used to better understand the property and for decision-making in regard to the next planting.

Yield monitoring systems typically utilize a mass flow sensor for continuous measuring of the harvested weight of the crop. The sensor is normally located at the top of the clean grain elevator. As the grain is conveyed into the grain tank, it strikes the sensor and the amount of force applied to the sensor represents the recorded yield. While this is happening, the grain is being tested for moisture to adjust the yield value accordingly. At the same time, a sensor is detecting header position to determine whether or not yield data should be recorded. Header width is normally entered manually into the monitor and a GPS, radar or a wheel rotation sensor is used to determine travel speed. The data is displayed on a monitor located in the combine cab and stored on a computer card for transfer to an office computer for analysis. Yield monitors require regular calibration to account for varying conditions, crops and test weights.

Instantaneous yield monitors are currently available from several manufacturers for all recent models of combines. They provide a crop yield by time or distance (e.g. every second or every few metres). They also track other data such as distance and bushels per load, number of loads and fields.  

3. Field Mapping with GPS (and GIS)

GPS technology is used to locate and map regions of fields such as high weed, disease and pest infestations. Rocks, potholes, power lines, tree rows, broken drain tile, poorly drained regions and other landmarks can also be recorded for future reference. GPS is used to locate and map soil-sampling locations, allowing growers to develop contour maps showing fertility variations throughout fields. The various datasets are added as map layers in geographic information system (GIS) computer programs. GIS programs are used to analyze and correlate information between GIS layers. Examples of the mapping would include:

• Soil Sampling

 Collecting soil samples across a large property can be organized using GPS and mapping software. The sample locations can be way pointed in the field and those waypoints marked on the mapping software. Then, when the laboratory results are returned the data can be plotted on the maps and decisions for soil treatment can be made for various parts of the property. The locational information can save money and time by allowing variable rate applications and treating only those areas with a documented need.

Soil Sampling methods include:

     1. Grid Sampling- intensive sampling of entire field

-Data collected for each cell or point.

-Multiple samples combined into each cell or point sample.

     2. Directed sampling:  intensive sampling of particular target areas.

-Sampling zones established based on knowledge of field

-GPS used to locate sample points.

-Areas of interest intensely sampled, others lightly sampled.

An example of a semi-automated Soil Sampler

• Weed mapping and Pest mapping

A farmer can map weeds while combining, seeding, spraying or field scouting by using a keypad or buttons hooked up to a GPS receiver and data logger. These occurrences can then be mapped out on a computer and compared to yield maps, fertilizer maps and spray maps. The same procedure is used while mapping pests in a field.

• Crop duster targeting

Insects don't attack a field with a uniform distribution. Instead outbreaks of insect activity are concentrated in certain areas. Workers strolling the crops can use a GPS to record the locations of insect problems. The data can then be used by crop-duster pilots to selectively target the problem areas instead of treating an entire field. This method results in a savings of time, fuel, insecticide and crop exposure to chemicals.

• Salinity mapping

GPS can be coupled to a salinity meter sled which is towed behind an ATV (or pickup) across fields affected by salinity. Salinity mapping is valuable in interpreting yield maps and weed maps as well as tracking the change in salinity over time.

• Topography and boundaries

Using high precision DGPS a very accurate topographic map can be made of any field. This is useful when interpreting yield maps and weed maps as well as planning for grassed waterways and field divisions. Field boundaries, roads, yards, tree stands and wetlands can all be accurately mapped to aid in farm planning. 

4. Precision Crop Input Applications/Variable rate applications

Crop advisors use rugged data collection devices with GPS for accurate positioning to map pest, insect, and weed infestations in the field. Pest problem areas in crops can be pinpointed and mapped for future management decisions and input recommendations. The same field data can also be used by aircraft sprayers, enabling accurate swathing of fields without use of human “flaggers” to guide them. Crop dusters equipped with GPS are able to fly accurate swaths over the field, applying chemicals only where needed, minimizing chemical drift, reducing the amount of chemicals needed, thereby benefiting the environment.

GPS technology is used to vary crop inputs throughout a field based on GIS maps or real-time sensing of crop conditions. Variable rate technology requires a GPS receiver, a computer controller, and a regulated drive mechanism mounted on the applicator. Crop input equipment such as planters or chemical applicators can be equipped to vary one or several products simultaneously.

Variable rate technology is used to vary fertilizer, seed, herbicide, fungicide and insecticide rates and for adjusting irrigation applications. Variable rate controllers are available for granular, liquid and gaseous fertilizer materials. Variable rates can either be manually controlled by the driver or automatically controlled by an on board computer with an electronic prescription map. E.g, by knowing weed locations from weed mapping spot control can be implemented. Controllers are available to electronically turn booms on and off, and alter the amount (and blend) of herbicide applied.
An example of a Variable Rate prescription map

5. Yield mapping
GPS receivers coupled with yield monitors provide spatial coordinates for the yield monitor data. This can be made into yield maps of each field. 

6. Tracking Livestock: 
The location of valuable animals on a large farm can be monitored by GPS transmitters attached to the animals collar. When the animals are sent to market GPS transmitters can also be used to track their location.

7. Records and analyses
Precision farming may produce an explosion in the amount of records available for farm management. Electronic sensors can collect a lot of data in a short period of time. Lots of disk space is needed to store all the data as well as the map graphics resulting from the data. Electronic controllers can also be designed to provide signals that are recorded electronically. It may be useful to record the fertilizer rates actually put down by the application equipment, not just what should have been put down according to a prescription map. A lot of new data is generated every year (yields, weeds, etc). Farmers will want to keep track of the yearly data to study trends in fertility, yields, salinity and numerous other parameters. This means a large database is needed with the capability to archive, and retrieve, data for future analyses. 

GPS APPLICATIONS IN AGRICULTURE

In the past, it was difficult for farmers to correlate production techniques and crop yields with land variability. This limited their ability to develop the most effective soil/plant treatment strategies that could have enhanced their production. Today, more precise application of pesticides, herbicides, and fertilizers, and better control of the dispersion of those chemicals are possible through precision agriculture, thus reducing expenses, producing a higher yield, and creating a more environmentally friendly farm. Site-specific agriculture, target farming, or precision farming, as some have called it, is an emerging approach to agriculture, which makes use of several of the latest technologies. The Global Positioning System (GPS), the subject of several posts in my blog now, is one of the key technologies that enable the practice of site-specific agriculture.
You may already be aware of the impact of GPS on agriculture, but perhaps it would be useful to review some of those applications before we get started. GPS technology gives us the opportunity to accurately determine our geographical position, and to use that position measurement in various agricultural operations. Yield mapping, for example, is an important application of GPS. If we can measure our yield while harvesting, and link that data with position data, then display it in the form of a map, we can learn valuable lessons about the production of our land. If we can link soil sample data, topography, weed and insect pressures, salinity and other soil conditions to position data, we can learn much about our farming practices. And if we can use position measurements to apply seed, fertilizer and chemicals strategically to optimize their effectiveness while minimizing costs, we can improve our bottom line.Several benefits are achieved from an automated method of capturing, storing and analyzing physical field records. Detailed analyses of the farm production management activities and results can be carried out. Farmers can look at the performance of new varieties by site specific area, measure the effect of different seeding dates or depths and show to their banker the actual yields obtained and the associated risk levels. It is imperative that trends and evaluations are also measured over longer time spans. Cropping strategies to control salinity may take several years to evaluate while herbicide control of an annual weed should only take one season. Precision farming can be approached in stages, in order to ease into a more complex level of management.


Precision agriculture is now changing the way farmers and agribusinesses view the land from which they reap their profits. Precision farming allows for improved economic analyses. The variability of crop yield in a field allows for the accurate assessment of risk. For example, a farmer could verify that for 70 % of the time, 75 % of the barley grown in field "A" will yield 50 bushels. By knowing the cost of inputs, farmers can also calculate return over cash costs for each acre. Certain parts of the field which always produce below the break even line can then be isolated for the development of a site-specific management plan. Precision farming allows the precise tracking and tuning of production.


Precision agriculture is about collecting timely geospatial information on soil-plant-animal requirements and prescribing and applying site-specific treatments to increase agricultural production and protect the environment. Where farmers may have once treated their fields uniformly, they are now seeing benefits from micromanaging their fields. Precision agriculture is gaining in popularity largely due to the introduction of high technology tools into the agricultural community that are more accurate, cost effective, and user friendly. Many of the new innovations rely on the integration of on-board computers, data collection sensors, and GPS time and position reference systems.

Many believe that the benefits of precision agriculture can only be realized on large farms with huge capital investments and experience with information technologies. Such is not the case. There are inexpensive and easy-to-use methods and techniques that can be developed for use by all farmers. Through the use of GPS, GIS, and remote sensing, information needed for improving land and water use can be collected. Farmers can achieve additional benefits by combining better utilization of fertilizers and other soil amendments, determining the economic threshold for treating pest and weed infestations, and protecting the natural resources for future use.

GPS equipment manufacturers have developed several tools to help farmers and agribusinesses become more productive and efficient in their precision farming activities. Today, many farmers use GPS-derived products to enhance operations in their farming businesses. Location information is collected by GPS receivers for mapping field boundaries, roads, irrigation systems, and problem areas in crops such as weeds or disease. The accuracy of GPS allows farmers to create farm maps with precise acreage for field areas, road locations and distances between points of interest. GPS allows farmers to accurately navigate to specific locations in the field, year after year, to collect soil samples or monitor crop conditions.

BENEFITS OF USING GPS ON THE FARM

•  Precision soil sampling, data collection, and data analysis, enable localized variation of chemical applications and planting density to suit specific areas of the field.
•  Accurate field navigation minimizes redundant applications and skipped areas, and enables maximum ground coverage in the shortest possible time.
•  Ability to work through low visibility field conditions such as rain, dust, fog and darkness increases productivity.
• Accurately monitored yield data enables future site-specific field preparation.
• Elimination of the need for human "flaggers" increases spray efficiency and minimizes over-spray. 

Precision farming should not be thought of as only yield mapping and variable rate fertilizer application and evaluated on only one or the other. Precision farming technologies will affect the entire production function (and by extension, the management function) of the farm. A brief overview of the components in precision farming are shown in Figure 1. and listed below. 

Figure 1.

·         Equipment/Tractor guidance Systems,

·         Yield monitoring Systems,

·         Field mapping Systems,

·         Variable rate applications/precision crop input applications

·         Yield mapping Systems

·         Tracking livestock

·         Crop scouting

·         Records and analysis Systems

There are, potentially, many ways that GPS can be used to strengthen our farm management practices. Some of these are still only ideas, others have already proven their potential. One thing is sure: GPS is a powerful tool, and one that promises much if we can effectively harness its power. But it is only one of several technologies, scientific disciplines and--that old difficult-to-define quality--‘common sense’, that must work together to deliver the necessary results. Ongoing efforts to apply these technologies continue on several fronts. Technology must be blended with agronomic knowledge and proven management practices in ways that have never been done before. As we continue to apply the new technology to the age-old field of agriculture, the challenge, as always, is to acquire the knowledge and skills, which will take us where we want to go. This blog is a part of that process.

HOW TO USE THE GPS

Using a GPS is quite simple, your GPS receiver is designed to ‘listen’ for the signals from four of those satellites, and use the info provided to determine your latitude and longitude. It overlays that unique point onto a map that resembles your surrounding area to help you to navigate your way to anywhere in the world. Although GPS receivers are affordable, many consumers still wonder if they have the skill to use one. When you consider that the GPS must send a signal to satellites orbiting the Earth, wait to receive a signal back, and then convert that signal to not only your location but the speed at which you're travelling and how long it will take you to reach a particular destination, the gadget can seem pretty fantastical and intimidating. But the truth is, the receiver does the bulk of the work itself. If you can navigate by map and compass, reading a GPS will be an easy skill for you to learn. Let's get started...

Operating a GPS unit is very simple

• Let the receiver “wake up”.
• Read the coordinate.
• Check the sky map and signal strength.
• Mark waypoints.
• Alternatively, begin a track.
• Record the waypoint and notes in the field notebook.

In more detailed form OF HOW TO USE THE GPS …

GPS Waypoint and Go-to

To accurately determine your location, a GPS receiver needs to lock onto four different satellites. The signal it receives from these satellites must be strong. If the signal is weak or the GPS receiver cannot lock onto four satellites, the information you receive may not be accurate.

To get a signal, turn the GPS receiver on and push the satellite button. It may take a few minutes, but you'll be able to see the number, location and strength of the satellites that the GPS receiver is locked onto. If the signal is weak, or there are less than four satellites on the screen, you should navigate using a map and compass.

Sometimes the area where you're standing can have an effect on your signal strength. If the signal is spotty or weak, try moving to a location without any overhead obstructions. Both trees and canyon walls can interfere with the GPS's ability to communicate with satellites. Move into a meadow or a parking lot while the GPS system locks onto the satellites. Once it has locked on, the receiver usually can maintain a connection when you enter the woods.

Two important functions of a GPS receiver are the waypoint and the go-to functions. Waypoints are points that you can enter into the memory of your GPS for a particular activity. They may be the spot you plan to start cultivating or planting, where you start levelling the field or irrigating the crop. You can enter more than one waypoint for each activity. As you proceed with the activity, you can see the waypoints and your relationship to them on the GPS screen.

The go-to function guides you exactly where you want to go. When you're ready to head to any point in your field or another field, simply press the go-to button, and a selection of waypoints will appear on your screen. Select the waypoint you want, and the GPS receiver will immediately let you know how far away it is and what direction you need to travel to get there. It will continually update as you move, so you'll know if you're drifting off course and how much farther you need to travel.

Laying a Track with GPS

Laying a track is another important GPS receiver skill. You can use your GPS to leave a virtual trail, which allows you to follow your trail out if you become lost. Your GPS will have a button that's responsible for dropping track points. You can drop the track points as close together or as far apart as you like. The closer together you place your track points, the more accurate this trail will be if you have to follow it out. When you use the tracking feature, you don't need to manually enter the track points, the GPS will automatically mark them for you at the distance you specify before your trip.

All of the features available on GPS receivers are nice to have, but these features come with a drawback. GPS receivers can be hard on batteries. Lithium batteries have the longest battery life, but may cause distracting lines across the GPS screen when they're new. To eliminate this problem, many people use lithium batteries in another piece of equipment for a few minutes before putting them in their receiver.

You can prolong the life of your batteries, no matter what type they are, by turning off nonessential functions. Backlighting, compass mode and other auxiliary functions can be switched off. Also, if your GPS loses its satellite lock, turn it off to conserve battery power until you find an open area to lock in on the satellites again.

IT'S NO MAP AND COMPASS: A GPS receiver is many things, but it's not a replacement for a map and compass. Batteries can die, satellite lock can be lost, and many other things can happen that render the GPS receiver ineffective.

Loading Maps onto GPS

GPS receivers are only as good as the maps they're used with. If you're proficient with a map and compass, then you're probably familiar with the various types of topography maps. Regardless of where you plan to travel/work on, it's important you have accurate and easy-to-read maps.

Your receiver will come loaded with a variety of maps. If the maps you want aren't preloaded onto your GPS, you can probably purchase them in CD-ROM format and load them onto your receiver. Some companies also provide microSD memory cards that are preloaded with maps that can easily be added to your GPS. Finally, the Internet has a wealth of downloadable maps available for receivers.

GPS receivers are bound to become a more intimate part of our lives as more people become comfortable with the technology. Some people first learn to use them through their jobs. More and more workplaces are using GPS to track company vehicles or employees who work outside the office.

Once you become proficient with a GPS receiver, you may find you're interested in adding one to your vehicle. GPS receivers are not capable of recognizing obstacles in their paths, so both a road detour or a rushing river will require you to reconsider your route. For this reason, it's unlikely that maps will become obsolete any time soon.Farmers and agriculture service providers can expect even further improvements as GPS continues to modernize. In addition to the current civilian service provided by GPS, the United States is committed to implementing a second and a third civil signal on GPS satellites. The new signals will enhance both the quality and efficiency of agricultural operations in the future.

THE GLOBAL POSITIONING SYSTEM (GPS) AS AN ICT IN AGRICULTURE

AN INTRODUCTION TO THE GPS AND HOW IT WORKS

While originally a military project, GPS is considered a dual-use technology, meaning it has significant military and civilian applications. The GPS has become a widely deployed and useful tool for use in agriculture. You may have heard how the use of GPS is revolutionizing the agriculture industry from finding your way to the middle of a corn field and accurate field guidance without foam markers, to critical row-crop driving and precise elevation mapping. But what is it? Even the development and implementation of precision agriculture or site-specific farming has been made possible by combining the Global Positioning System (GPS) and geographic information systems (GIS). These technologies enable the coupling of real-time data collection with accurate position information, leading to the efficient manipulation and analysis of large amounts of data. GPS-based applications in precision farming are being used for farm planning, field mapping, soil sampling, tractor guidance, crop scouting, variable rate applications, and yield mapping. GPS allows farmers to work during low visibility field conditions such as rain, dust, fog, and darkness. In the past, it was difficult for farmers to correlate production techniques and crop yields with land variability. This limited their ability to develop the most effective soil/plant treatment strategies that could have enhanced their production. Many of the new innovations rely on the integration of on-board computers, data collection sensors, and GPS time and position reference systems.

The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible by anyone with a GPS receiver with some technical limitations which are only removed for military users. GPS was created and realized by the U.S. Department of Defense (USDOD) and was originally run with 24 satellites. It became fully operational in 1994.In addition to GPS, other systems are in use or under development. The Russian GLObal NAvigation Satellite System (GLONASS) was in use by only the Russian military, until it was made fully available to civilians in 2007. There are also the planned European Union Galileo positioning system, Chinese Compass navigation system, and Indian Regional Navigational Satellite System.

A GPS determines the absolute location on Earth as coordinates from satellite signals with a GPS System consisting of:

• 24 - 32satellites orbiting the Earth;
• A control station that monitors the satellites;
• A  hand-held receiver.

A GPS system can be divided in to the three main categories: space segment, control segment and user segment.

1. Space segment consists of satellites that are placed in altitude of 20,200 from the earth. There are 24 to 32 satellites that send all the GPS signals to the earth.
2. The control system consists of monitoring stations that are located in the world. These stations monitor the satellites and that helps to calculate the orbits and ephemeris data.
3. The last segment, user segment, means the GPS receivers that are used to receive GPS data from the satellites. The GPS receivers used to be separate devices, but now most of them are integrated into different devices. GPS receivers are now even integrated in many mobile phones. The GPS receivers can receive and process data from many satellites simultaneously. 

There are 24 – 32 GPS satellites orbiting the planet in six orbital planes; the more satellites a reference station can track simultaneously, the more accurate the spatial data it provides.

HOW THE GLOBAL POSITIONING SYSTEM WORKS.

The principles of how GPS works are understood through the concepts of triangulation and that distance is measured by how long it takes a signal to get from one point to another. GPS uses the principle of triangulation to three or more satellites. The satellites that are travelling around the world twice a day send radio signals that contain originated time of the message, the ephemeris data than can be used to calculate the position of the satellite in orbit and also the almanac, the status of all the satellites in the system. These almanac data can be stored in the receiver too as the satellites rotate in the same orbit, but because of the gravity of the moon and the sun, satellites can change the orbits slightly from time to time. That’s why the up-to-date almanac data is also coming with the GPS signals. To measure its own location, the GPS receiver should know at least the location of three satellites and the distance from each of them to the receiver. The receiver calculates the time that it has taken the signal to travel between the satellite and the receiver. And then assuming that the signal travelled in a straight line, as radio signals travel in the same speed as the speed of light in free space, the receiver multiplies the time by the speed of light to measure the distance between each satellite and the receiver. (Light and Radio waves both being Electromagnetic waves travel at the same speed, which is the speed of light, in a vacuum. When propagated through a medium though, they are slowed down according to permeability and permittivity of the medium: C = 1/sqrt(Permeability * Permittivity). Air has nearly normal permeability and permittivity so in practice they do travel at nearly the speed of light). 

If the receiver knows the distance to at least three satellites in a given time, and if we assume there are no errors in the measuring, it can use three dimensional trilateration to measure its location. Simple explanation for trilateration is that you can calculate the coordinates of a given position if you know the distance from it to another three known positions in two dimensional space. In dimensional trilateration you need distance at least to four different known locations. In this case, you can draw spheres that have each satellite’s location as the centre and the distance between that satellite and the receiver as the radius. The intersections of these spheres can give the location of the receiver. But when you have only three known satellites, there can be two places that intersect. So to get the correct place, the receiver uses the earth as another sphere as the given position should be on the earth. So that gives the correct location of the receiver.

Even though the method looks very simple, the little difference in the clocks of the receiver and the satellites can cause a huge difference of the calculated location and actual location, because the speed of the light is quite high and multiplication with it can make a small error a huge one. To avoid that, the receiver and the satellites have to have synchronized clocks up to nanoseconds accuracy. Using atomic clocks can solve that problem, but since they are very expensive, using them in every receiver will not be very usable as it can increase the price of the receiver beyond the day today user limits. GPS systems therefore use the following method to avoid that problem: The receiver gets the signals from four or more satellites and the spheres that associate with each satellite have to intersect in single position. If not it’s because of the clock error of the receiver. So the receiver can calculate the error as it’s proportional to the distance. Then it can correct the error and calculate the exact location. That’s why the receiver has to get the signals from at least four satellites to calculate the position of the receiver accurately (although three are enough to calculate the location). An important aspect of GPS technology to keep in mind is that it is not two dimensional, but three dimensional. All too often we think of maps and GPS as something that provides points and coordinates for a position on the surface. GPS systems certainly perform this function, but they provide a measure of vertical position as well as horizontal. The implications of centimetre-level accuracy for GPS are amazing.

Let us leave the technical part of the GPS and as agriculturalists look more into practical applications of the GPS in agriculture. The purpose of this blog is to provide you with a basic understanding of how GPS technology works and how it can be implemented in agriculture. This will help you make good decisions about your own involvement in this new field. You will gain a basic understanding of GPS technology and terminology, but I will not delve into the electronics of GPS receivers, or the mathematics of geomatics... But first a mention of types of GPS units, how to use a GPS and much more GPS-wise. Catch me on my next blog

WELCOME ABOARD MY BLOG

AGRICULTURE AND EVERYTHING ICT...
Ever stopped for a moment to consider the practical effects of technology in your life? Perhaps you have, and you may have marvelled at what a unique time in history we live. The last generation has probably experienced more technological change than any other in history. Breakthroughs that once might have rocked our perceptions of the world have become almost mundane, a regular occurrence. Sometimes it becomes difficult to evaluate their real significance. However, your logging on to this blog indicates that you have caught at least a glimpse of that significance in one area, that of the application of Information and Communication Technologies in agriculture, one of the most significant uses of ICT and one that is growing with immense speed.

When I wake up in the morning and having said my prayer, the first thing I do is to power my computer, and this I can do without rolling out of my bed. I leave it to boot and check my phone for any missed calls or messages or any delivered emails, (through an sms notification, thanks to my service provider). I turn on the radio to get in touch with the latest in news and log online on to the local daily to read the news in real time - then I know my morning has began. This is how ICT filled my day is, looking that this is just the first 5 minutes of start of my day. In this era, I am certain that the lives of most people are just as ICT filled as mine, or even more. As you use your laptop or tablet to do some work while stuck in traffic on your way to work, or as you use your phone to make or receive that important call, send sms, chat online or on your phone, blog, skype - we are all ICT incorporated.

 WHY AGRICULTURAL DEVELOPMENT?

Three-quarters of the world’s poorest people get their food and income from farming small plots of land—typically the size of a football field or smaller—and most of them labour under difficult conditions. They grow a diversity of local crops and must deal with unique diseases, pests, and drought, as well as unproductive soil. Their livestock are frequently weak or sick, resulting in reduced production of eggs and milk to eat or sell. Reliable markets for their products and good information about pricing are hard to come by. Most often, government policies do not adequately serve their interests.

The need to improve agricultural productivity is clear:

• •Severe hunger and poverty affects nearly 1 billion people around the world.
• • By 2050, it’s estimated that the earth’s population will reach 9 billion. Global food production will need to jump by 70 percent to 100 percent to feed these people. Rising incomes, increasingly scarce resources, and a changing climate are putting additional strains on agricultural productivity.
• •  Two billion people in the developing world are malnourished. Malnutrition continues to be the world’s most serious health problem and the single biggest contributor to child mortality.

The power of investing in agriculture is clear: Agricultural development is two to four times more effective at reducing hunger and poverty than any other sector.Improvements in agricultural productivity certainly create social and economic ripple effects, and putting in to consideration all aspects of agriculture, ICT needs to be incorporated to help this sector grow. ICT and agriculture is a field focusing on the enhancement of agricultural through improved information and communication processes. More specifically, it involves the conceptualization, design, development, evaluation and application of innovative ways to use information and communication technologies with a primary focus on improving support and innovation in agriculture. In ACP countries, ICT in agriculture is a relatively new term and we fully expect its scope to change and evolve as our understanding of the area grows, I will play my part through my blog.

We live in an information age characterized by global expansion in mass media, through electronic "super-highways" that span the globe. But there is concern that the gap between the information rich and the information poor widens. Rural communities are still difficult to reach - they lack communication infrastructure such as newspapers, telephones, televisions and radios. In rural areas of Africa, the challenge of bridging this information gap involves not only increasing the quantity and accessibility of communication technologies but also improving the relevance of the information to local communities. Some information and communication technologies and know-how exist, the challenge is how to use them effectively for sustainable agricultural and rural development and especially for improved food security.

Various science and technology issues emerge to enable Africa achieve food security and sustainable development and we should work to develop and incorporate ICT systems that can handle all these.  The major science and technology issues include:

• Developing agricultural technology for meeting the increasing need for food at affordable prices;
• Developing sustainable land management technologies for rangeland, forestland, grassland, swampland, marginal land, etc.;
• Developing agricultural systems that conserve biodiversity within the system itself; and
• Developing knowledge systems based on proper understanding of needs of households that depend on the ecosystem and indigenous knowledge of existing resources for their survival.

Touching on the main phases of  the agriculture industry : Crop cultivation, Animal production, Water management, Fertilizer application, Fertigation, Pest management, Harvesting, Post harvest handling, Transporting of food/food products, Packaging, Food preservation, Food processing/value addition, Food quality management, Food safety, Food storage, Food marketing, ICT is so vital in their deveolpment. All stakeholders of the agriculture industry need information and knowledge about these phases in order to manage them efficiently. Any system applied for getting information and knowledge and for making decisions in any industry should deliver accurate, complete, concise information in time or on time. The information provided by the system must be in user-friendly form, easy to access, cost-effective and well protected from unauthorized accesses.

Any ICT system that is adopted in agriculture, be it GIS,GPS, radio, TV, video, internet or the telephone, should be able to perform most, if not all, of the functions listed below. The better an ICT system, the more functions it can incorporate. These functions include:

·         Record text, drawings, photographs, audio, video, process descriptions, and other information in digital formats,

• Produce exact duplicates of such information at significantly lower cost,
• Transfer information and knowledge rapidly over large distances through communications networks.
• Develop standardized algorithms to large quantities of information relatively rapidly.
• Achieve greater interactivity in communicating, evaluating, producing and sharing useful information and knowledge.

In my blog, I shall touch on ICT systems available for use in agriculture and how they can be applied in the agriculture sector for its development. I want to share ICT skills and knowledge that must be involved in the technological learning and implementation of technological policies for sustainable agriculture, thus sustainable development. I will blog on ICT systems with the main focus of providing a marketable skill to improve agricultural practices and outputs countrywide, in extension worldwide.