The Graphic Overlay Method

Soil Survey and Association Examples
Homepage  |  Introduction  |  Map Features  |  Feature Measurements  |  Coding
Value Added Maps  |  Elevation Maps  |  Soil Survey Maps  |  Soil Attributes
Soil Characteristics  |  Combining Strategy  |  Process Map  |  Solution Map 
The map (below) is Section 28 of the United States Soil Conservation Service, United States Department of Agriculture, (SCS, USDA)  Soil Association map in Rapides Parish, Louisiana.  Similar paper booklets, and accompanying maps, are available for most areas in the United States. The original (paper) map scale is 1:20,000. 
Numbers (1-10) have been added to the survey map for a second easy reference.  Yes, this is a "paint by numbers" coding scheme that assigns a value to a specific land area based on accompanying tables of scientific information. 
The three digit numbers in brackets [999] reference Berol Prismacolor pencils colors. 

The attributes (characteristics) are actually hand (color) coded using standard colored pencils.  You can enhance your understanding of these coding concepts if you will print this page and try and replicate the value added maps (by actually coloring an example or two) using the following Soil Attribute Table as a reference.  

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All contents copyright (C) 1993-1999,  D. Fehler  All rights reserved.