The raster revision process combines the scanned content of paper maps with raster updating technologies. The vector revision process involves the automated plotting of updated vector files. Traditional processes use analog stereoplotters and manual scribing instruments on specially coated map separates. The ability to select from or combine these processes increases the efficiency of the National Mapping Division map revision program. In the complete revision process, all features are corrected and updated.
Content is validated by field checking against ground truth.
Contours are revised. The revised map meets all current National Mapping Division standards for feature content and National Map Accuracy Standards for positional accuracy. In the basic revision process, many features are revised through interpretation of image sources, such as orthophotos or aerial photographs. The features are not verified through ground truth, and contours are generally not revised. The revised map maintains the positional accuracy of the previously published map.