ESRI defines geoprocessing as a framework and set of tools for processing geographic related data. In GIS, there are different geoprocessing tools and techniques to perform spatial analysis or manage GIS data in an automated way. It is a very important tool in ArcGIS software and plays a fundamental role in spatial analysis. Geoprocessing can range from simple tasks to very complicated spatial analyses that aid to address an important spatial problem. For example, it is used to find the best groundwater wells in a basin that has high yield and good water quality, or the best location to build a treatment plant, etc. Besides, it is used to perform essential operations on a database, such as projections, conversions, data management, spatial analysis, and others.
There are number of geoprocessing tools in ArcGIS. Some of them are categorized below based on their function:
- Extracting features
- Clip: This tool is used to clip out a part of an image or raster in ArcGIS. The shape defining the clip can include the extent of the raster or an area within the raster.
- Erase: It is used to create a feature class by overlaying the input features with the polygons of the erase features. Only those portions of the input feature falling outside the erase features outside boundaries are copied to the output feature class. Input Feature geometries coincident with Erase Feature geometries will be removed.
- Split: This geoprocessing tool splits an input with overlaying features to create a subset of output feature classes. The Split Field parameter’s unique values form the names of the output feature classes. These are saved in the target workspace.
- Combining features
- Merge: While using this tool, it created new parcels by merging existing parcels in the parcel fabric. Adjacent parcels can be merged to create a single parcel, and disjoint parcels can be merged to create multipart parcels.
- Append: It appends multiple input datasets into an existing target dataset. Input datasets can be feature classes, tables, shapefiles, rasters, annotation, or dimensions feature classes. To combine input datasets into a new output dataset, use the Merge tool.
- Dissolve: It dissolves features and creates a new aggregate feature based on a specified attribute.
- Buffer: It creates buffer polygons around input features to a specified distance. The two basic methods for constructing buffers, Euclidean, and geodesic. Euclidean buffers measure distance in a two-dimensional Cartesian plane, where straight-line or Euclidean distances are calculated between two points on a flat surface (the Cartesian plane). Geodesic buffers account for the actual shape of the earth (an ellipsoid, or more properly, a geoid). Distances are calculated between two points on a curved surface (the geoid) as opposed to two points on a flat surface (the Cartesian plane).
- Combining geometries and attributes
- Union: It computes a geometric union of the input features. All features and their attributes will be written to the output feature class.
- Intersect: It computes a geometric intersection of the input features. Features or portions of features that overlap in all layers and/or feature classes will be written to the output feature class.
- Spatial Join: A spatial join involves matching rows from the join layer to the target layer based on a spatial relationship and writing to an output feature class. When a match is found during processing, a row is added to the output feature class containing the shape and attributes from the target layer and the matching attributes from the join layer.
In ArcGIS, the geoprocessing tool can be assessed through toolbox, ArcObjects, Command line, Scripts, and ModelBuilder.