1998 Impervious Surface Data

Land Use/Land Cover and Impervious Surface

About the Tables

All raster files contain attribute information describing the values associated with the data number.  There are four descriptors worth mentioning —

· Color — attribute that assigns a gray scale value ranging from very light gray (1%) to black (100%)

· Class_Name — Percentage of the area enclosed by the pixel that is computed to be impervious.

· Histogram — the total count of the number of occurrences of a Class_Name value within the  raster dataset.

· Acres and Hectares — Area computation based upon the histogram * area of each pixel.  Since the pixel size is 30m x 30m, the computations for Acres and Hectares are

· Acres = Histogram * 247.105

· Hectares = Histogram

Since the Albers Conical Equal Area is used for these data, area computations should be accurate for all areas of the State of Alabama.

Tabular information in the Raster Data