Horizontal accuracy can be affected by errors in horizontal positioning of features, or errors in recording horizontal datum. Horizontal accuracy may differ between sources. In some cases, it may also differ within sources, if multiple sources were used. For example, DTED Level 1 data contained data from various cartographic sources, as well as from various types of imagery. If individual map sources had errors in recorded horizontal datum, or had misplaced contour lines (as could happen during compilation or in printing), the resultant DEM would be misplaced horizontally, in an undocumented fashion. If individual sources of imagery had errors in image navigation, resultant DEMs could be mislocated if these errors were not corrected during development of respective DEMs.

7.A.i. Data from Raster Data Sources
7.A.ii. Data from Cartographic Sources