Geoscience Reference
In-Depth Information
10
Integration of Geographic
Information Systems (GISs)
with Agricultural Geophysics
Carolyn J. Merry
ContentS
10.1 Introduction ......................................................................................................................... 199
10.2 Components of a GIS .......................................................................................................... 199
10.3 Mapping Concepts ..............................................................................................................200
10.4 Common Coordinate Systems.............................................................................................204
10.5 Spatial Databases ................................................................................................................206
10.6 Acquisition of Nongeophysical Spatial Data....................................................................... 207
10.7 GIS Models and Modeling .................................................................................................. 207
10.8 Summary............................................................................................................................. 208
References ...................................................................................................................................... 208
10.1 IntRodUCtIon
Proper agricultural management decisions often require the integration and analysis of information
from a number of different sources, including measurements obtained from one or more geophysi-
cal methods (resistivity, electromagnetic induction, ground-penetrating radar, etc.) along with other
farm field geospatial data (topography, crop yields, soil properties, satellite remote sensing imagery,
etc.). Integration and analysis of geophysical and nongeophysical information from multiple sources
is especially important when employing precision agricultural techniques to separately manage dif-
ferent parts of a farm field. Geographic information systems (GISs) provide a set of tools that are
particularly well suited for management, integration, and analysis of multiple geophysical and non-
geophysical geospatial data sets. GIS software essentially allows geospatial data to be organized,
stored, edited, displayed, and analyzed in an effective and efficient manner.
10.2 CoMponentS of A GIS
There are four basic components to a GIS: an input system, a database management system which
includes data storage and editing, a data analysis system, and an output system (Figure 10.1). Basic
functions within a GIS include data acquisition, data management, data manipulation, data analysis,
modeling, and the display of spatial data. The input system to a GIS allows the user several different
ways to incorporate data. Data input devices, such as digitizing tables and scanners, allow one to
incorporate historical data from existing hard-copy maps. Software utilities are available to import
data in various standard formats, such as ASCII, shapefiles, .tif, .img, and .dxf.
The database management system is the core of the GIS. The geospatial data will be in various
computer formats in the database—vector data, raster data, shape files, and the attribute informa-
tion. The database is typically in a standard format, depending on the GIS software. Data storage
199
