z-value
vertical datum
topographic map
DRG
GeoTIFF
collar
contour line
contour interval
US Topo
DTM
two-and-a-half-dimensional (2.5D) model
three-dimensional (3D) model
TIN
DEM
NED
viewshed
slope
slope aspect
SRTM
LIDAR
LAS
pseudo-3D
perspective view
hillshade
Sun altitude
Sun azimuth
draping
base heights
vertical exaggeration
433