1990 Land Use Data

Land Use/Land Cover and Impervious Surface

Land Use map of northern Baldwin County, Alabama.

Data Description

The main objective of the National Land Cover Data (NLCD) project was to generate a generalized and nationally consistent land cover data layer for the entire conterminous United States.

The land cover data sets are single band raster images. All data are projected to Albers Conical Equal Area using the NAD83 Datum, GRS 1980 Spheroid, with a spatial resolution of 30 meters.

The National Land Cover Dataset was compiled from Landsat satellite TM imagery (circa 1992) with a spatial resolution of 30 meters and supplemented by various ancillary data (where available). The analysis and interpretation of the satellite imagery was conducted using very large, sometimes multi-state image mosaics (i.e. up to 18 Landsat scenes). This evaluation must be made remembering that the NLCD represents conditions in the early 1990s. The Alabama portion of the NLCD was created as part of land cover mapping activities for Federal Region IV that includes the States of South Carolina, Florida, Georgia, Mississippi, North Carolina, Kentucky, and Tennessee. The NLCD classification contains 21 different land cover categories.

An unsupervised classification algorithm was used to classify the mosaicked multiple leaf-off TM scenes. Aerial photographs were used to interpret and label classes into land cover categories and ancillary data sources resolved the class confusion. Further land cover information from leaf-on TM data, NWI data, and other sources were incorporated to refine and augment the "basic" classification.