Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

Setting the General and Raster Environment

When you are using vector feature datasets the bounding rectangle of the data pretty much takes care of itself, once you set the coordinate system. Not so with raster data. The raster is a rectangle, and when you combine rasters, you want them to represent the same area. So, we will set the output extent—in this case to the extent and projection of the vector feature class Soils.

____ 2. Start ArcMap with a Blank Map. Dismiss ArcToolbox, if it is present. Add as data

___ IGIS-Arc_YourInitials\Spatial_Analyst_Data\

WC_Boat_SA\Wildcat_Boat_SA.mdb\Area_Features\Soils

Choose Geoprocessing > Environments > Workspace. Make both the Current Workspace and the Scratch Workspace

___ IGIS-Arc_YourInitials

____ 3. For the Output Coordinates, browse to

___ IGIS-Arc_YourInitials\Spatial_Analyst_Data\

WC_Boat_SA\Wildcat_Boat_SA.mdb\Area_Features\Soils

The Output Coordinate System should be set to “As Specified Below”. For the coordinate system browse to Projected Coordinate Systems > UTM > WGS 1984 > Northern Hemisphere > UTM_Zone_18. Scroll down to Processing Extent and again browse to Soils. The four bounding values should appear. Write them here (to the nearest one-tenth meter).

Top ________________ Bottom ________________

Left ________________ Right __________________

____ 4. Scroll down further and click Raster Analysis. Click the Cell Size drop-down menu and pick “As Specified Below”. Type in 2.0. OK the Environment Settings window. ...