What are DOQ

1
What are DOQ?

• Digital Orthophotoquad (DOQ) - A raster data
  theme, built from scanned aerial photography,
  rectified and mosaicked to form a planimetrically
  correct map-like product. Used as a base for
  digitizing features, or as a realistic backdrop
  for maps.
• Aerial photography of the Earth's surface,
  usually provided in GeoTIFF form, but also seen
  in other formats. A DOQ for a 7.5-min.,
  124000-scale quad is huge, thus the common use
  of DOQQs--digital orthophoto quarter quadrangles.
  
• is a digital image of an aerial photograph in
  which displacements caused by the camera and the
  terrain have been removed. It combines the image
  characteristics of a photograph with the
  geometric qualities of a map.

2
What are .e00 files?

• Data in .E00 is an ARC/INFO interchange file
  format. This is a simple ASCII file which can be
  opened and viewed using any common text editor
  (wordpad, notepad, textpad).

3
What are DEM?

• Digital Elevation Model (DEM) - Any data theme
  that digitally represents terrain (the shape of
  the earth's surface) the most common structures
  being a raster grid of elevations, and the vector
  triangulated irregular network (TIN).
• The USGS (United States Geological Survey) DEM
  (Digital Elevation Model) format describes raster
  elevation scans of the Earth's surface
  (essentially a specialized type of heightfield).
• A digital representation of the elevation of
  locations on the land surface. A DEM is often
  used in reference to a set of elevation values
  representing the elevations at points in a
  rectangular grid on the Earth's surface.

4
Digital Terrain Model (DTM)

• Digital Terrian Model(DTM) - A three-dimensional
  model of the Earth's surface, provided in digital
  form.
• A term that describes a variety of digital
  formats for displaying or analyzing elevation
  information. A DEM is one of these formats.

5
Digital Raster Graphics (DRG)?

• DRG is a scanned image of a US Geological Survey
  (USGS) standard series topographic map, including
  all map collar information. The image inside the
  map neatline is georeferenced to the surface of
  the earth and fit to the Universal Transverse
  Mercator projection.

6
What is Digital Line Graphs (DLG)?

• A vector file containing points, lines, and/or
  areas that represent roads, water bodies,
  topographic contour lines, public lands, and
  railroads. Each data layer comes in a separate
  file. The DLG format was created by the USGS.