This data set was derived by modifying a 1998 land use data layer for Rockingham County. Standards governing the development of the 1998 data are available in LUSTANDARDS.doc.
A countywide mosaic of the 74 orthophotography - 74DOM015 - is available from GRANIT (<URL:http://www.granit.sr.unh.edu/cgi-bin/nhsearch?dset=dom74/74dom015>). A companion data file - PHOTOPNT74 - may also be downloaded from the web site (<URL:http://www.granit.sr.unh.eduj/cgi-bin/nhsearch?dset=photopnt/photopnt74>). This point layer documents the name, photo centerpoint, date of acquisition, and other pertinent information for each photo used to create the mosaic.
In addition, code domain checks ensured that only valid codes were assigned to features, and polygon "dissolve" operations identified any cases where adjacent polygons shared the same land use code.
Using the documented photo sequence, on-screen digitizing/editing was performed to:
- eliminate any land use features that were not present in 1974 - redelineate, as necessary, any features that had changed from the earlier date
1. GRANITID - a 7-digit unique integer assigned sequentially to polygons in the data set.
2. LU - a 2-digit integer describing the land use feature, as follows:
Residential (11) - Individual houses, subdivisions and "in-town" residential areas Industrial/commercial (12) - Urban areas dominated by business operations Mixed urban (13) - Urban areas where commercial enterprise occupies part of a building/block and residential use occurs in another, adjacent part of the building/block. Also, miscellaneous urban uses, e.g. schools, military installations, etc. Transportation/roads (14) - Paved roadways, travel lane width, airports, or other public transportation features Railroads (15) - Railroad beds Auxiliary transportation (16) - Highway medians, clover leafs, etc. Playing fields/recreational (17) - Golf courses, baseball diamonds, football fields, etc. Agriculture (20) - Includes hay fields, row crops, fruit orchards, etc. Farmsteads (24) - Any buildings associated with farms Forested (40) - Land where trees are the dominant cover Water (50) - Open surface water Open wetlands (60) - Wetlands where the dominant vegetation is less than 20' in height Idle/other open (70) - Cemeteries, gravel pits, quarries, old fields, etc.