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Intermediate ArcGIS 9
   Landcover Analysis

Course Introduction
Getting Started
 - Landcover data
 - Getting the data
 - Layer files and MXDs
 - Changing symbology
 - Consolidating classes
 - Identify tool
Overview of data
Spatial Analyses
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Identify tool

Concepts:
   pixel values

The pixel value is the numeric value stored in the raster indicating what the pixel represents.  When using the ArcMap Identify tool, it will only return the pixel value of a TIFF or ArcSDE raster (this is because at ArcGIS 9.1, attribute tables for these rasters are not yet supported).

Thus, if you are using ArcMap and "Identify" a pixel, you will just see a number returned, rather than a landcover class.  In the case of canopy or impervious data, that number will indicate the percent impervious or canopy, but in the case of landcover data you have to look up the numeric value shown and find the related landcover class.  Therefore, the Identify tool is of limited use with TIFFs or ArcSDE rasters at this time (side note - at 9.2, attribute tables are supported in all rasters, presumably this will work better then).

image showing use of identify tool in ArcMap with landcover data

image showing identify results from landcover data
"Identifying" returns just the pixel value - 10 in this case.  User must look up what this means - Evergreen Forest in this case.
<Previous: Consolidating classes    Next: Overview of data>