(3) A University site licenses allows the SABINS project to digitize boundaries using the DOQQ
imagery provided by Esri and still maintain oversight of the attendance boundary vector data that are produced.
-- Because mapping error plays a critical role in determining the magnitude of shoreline change, two additional error assessment techniques were employed: the accuracy of the 1995 DOQQ was further assessed by collecting GPS positions of a number of Ground Control Points (GCPs) within the study area.
Overall, the assessment of error suggests a point accuracy of [+ or -] 1 m for both the DOQQ and GPS-based shoreline maps.
In each of the five areas, two different GIS specialists independently digitized the streamlines using two types of orthophotography (DOQQs
and local imagery).
Geological Survey (USGS) Digital Orthophoto Quarter Quadrangles (DOQQs
) licensed by the City of Seattle to the University of Washington.
For sites with canopy cover less than 10% (and often more open water), we estimated the area of open water using a digital orthoquad (DOQQ
) layer in ArcView 3.3 (ESRI, Redlands, CA) that was derived from 1992-1995 aerial photographs at 1:40,000 (U.S.
MAP (Example of Boat Ramp and Cahaba Lily Site at Bibb County)
Digital Orthophoto Quarterquadrangles (DOQQ
) -- a digital aerial photograph that covers one-quarter of the area of a topographic map.
An analysis of the October 1998 flood and the 100-year FEMA floodplain along the San Marcos River using DOQQ
The most reliable and the easiest-to-get digital GIS data sources are probably the Digital Line Graphs (DLG), Digital Elevation Models (DEM), Digital Orthophoto Quad Quadrangle (DOQQ), and Digital Raster Graphics (DRG) data that are available from the U.S.
Geological Survey (USGS) DLG, DRG, DOQQ, DEM, GNIS, National Atlas, Landuse, Landcover, GLIS Microsoft TerraServer Digital Orthophoto (originally from Soviet satellites and USGS DOQQ) EPA AILESP, NPL, Superfund, CERCLA water quality, environmental facility Michigan DNR MIRIS Databases.