Presentation on theme: "GPS/GIS Applications in Agriculture"— Presentation transcript:
1 GPS/GIS Applications in Agriculture Gary T. RobersonAgricultural Machinery Systems
2 Global Positioning System (GPS) Space and land based information system to determine precise position data.Utilizes military satellites to determine positioning information.Position based on trilateration from know satelite locations.Millions of GPS users worldwide.Most common type of system in agriculture.
3 Selecting GPS Components Hand HeldBackpackVehicle MountedRecreationalMappingSurveying
5 What Are Acceptable Accuracy Requirements? Variable fertilizer application(Swath control)Yield mappingVariable herbicide applicationSpray overlap controlRow crop plantingSeed bed formation30 m1 m10 m10 cm5 cm
6 Point Guidance Target point selected on map screen. Cursor location indicates present position, target position highlighted.Cursor provides guidance to target.
7 Swath GuidanceAnchor points established to create base line on map screen.Parallel lines generated at desired swath spacing.Can be used for straight or contour swathsLight bar or similar device used to provide guidance along line.Automatic steering possible.
8 Field MappingPosition data (georeference data) recorded at predetermined intervals.Other data recorded manually or automatically by monitor, computer, or data logger.Data displayed by geographic information system (GIS) in thematic map format.
9 Soil Sampling Georeferenced soil samples can be collected Sampling MethodsGrid sampling: intensive sampling of entire fieldDirected sampling: intensive sampling of particular target areas
10 Grid Sampling Data collected for each cell or point Multiple samples combined into each cell or point sample
11 Directed SamplingSampling zones established based on knowledge of fieldGPS used to locate sample points.Areas of interest intensely sampled, others lightly sampled
20 Variable Rate ControlApplication rates designed for needs of small sections of a fieldGPS determines position of equipment in the fieldComputer controls use GPS data and prescription files to adjust rate
22 Summary GPS/GIS hardware and software are valuable management tools. Accuracy requirements should be dictated by task requirements.Hardware and software should be selected to be compatible with the complete system.