San Diego Region 40 Foot Elevation Contours by Quad


COVERAGE NAME : topoqX (where X = the USGS 15 minute quad tile window)

COVERAGE DESCRIPTION: Elevation contour coverages for the region, tiled by
USGS 15' quads, at a 40' contour interval


EXTENT: USGS 7.5 minute quads covering the San Diego region

DATE OF DATA: Not Applicable (1970's, date on the USGS paper maps)

NUMBER OF RECORDS: varies by 15 minute quad

MAPPING SCALE: 1:24,000 (1" = 2000')

MAPPING SOURCE: Scanned mylars of contours from 1:24,000 USGS quad maps.

Notes: The USGS 7.5 minute contour data sets were created by SDSU using
procedures and standards provided by the USGS. The contour lines were
scanned. This raster data was then edited, vectorized, and attribute tagged.
These coverages contain information in quad areas that go outside the San
Diego region.

The individual quad data was only `visually' edgematched before merging to
create the 15 minute quads (therefore you will see over/under shoots (node
dangles) along the 7.5 minute quad boundaries. These are only visible when
zooming in to very large scales, or when node dangle display option is
used). The contours are generally represented at 40' contour intervals, but
the supplemental contours (in flatter areas) are also included within these
data sets. For USGS quads with a 20' contour interval, supplemental contours
are at 10' intervals. USGS quads with a 40' contour interval, have
supplemental contours at 20' intervals. Therefore there could be both 10'
and 20' contour increments in an area.

The elevation data is currently being distributed. Users may undoubtedly
have comments or find errors. If you find problems with any of the
information, please email your comments to the following email: Copies of comments will be directed to SDSU and to
SANDAG staff. New coverages may be provided at a later date.

Line Attribute Items:

         1        FNODE#     4       5         B     -       -
         5        TNODE#     4       5         B     -       -
         9        LPOLY#     4       5         B     -       -
        13        RPOLY#     4       5         B     -       -
        17        LENGTH     8      18         F     5       -
        25       TOPOQX#     4       5         B     -       -
        29     TOPOQX-ID     4       5         B     -       -
        33          CODE     5       5         I     -       -

Code documentation:

Code = Elevation values