09/12/2008
Topographic Contours for Hancock, Harrison, and Jackson Counties, MS

This readme file pertains to the following shapefiles:
MS_Hancock_Topo.shp
MS_Harrison_Topo.shp
MS_Jackson_Topo.shp

Horizontal Datum:  NAD 83, Mississippi State Plane, Zone East, ft
Vertical Datum:  NAVD 88, ft
Contour Interval:  2 ft

Data Description:

Each shapefile contains topographic contours calculated from LIDAR data collected by EarthData, Inc, for the 
National Oceanographic and Atmospheric Administration (NOAA) Coastal Services Center for and in conjunction 
with the State of Mississippi.  The data contained in these shapefiles is considered preliminary and has not been 
verified.  Final, verified data will be available from the NOAA Coastal Services Center in late December 2005 or
early January 2006.  Check http://ekman.csc.noaa.gov/TCM/ for final availability.  

Topographic elevation contour data contained in each file were created from 5m DEMs of the preliminary EarthData 
LIDAR point coverage for each county.  These contours were smoothed from the original topographic surface
in order to match the corresponding advisory base flood elevations (ABFEs).  The contours were clipped to the 
extent of the ABFE map panels.  Polyline segments for each elevation contour were planarized by 
the paneling scheme and therefore are not continuous through each county.   

Data fields:
CONTOUR:  Elevation Contour in ft relative to NAVD 88


**************5 Foot DEMS --- September 2008  ********

   A set of 5 ft DEMS were generated for each county using the above 2 ft contour lines 
 along with the 1:24,000 NHD streams and polygon water from USGS. The hydro data including the shoreline
was edited using the April 2007 6 inch and 1 foot imagery from the MS Coordinating Council for Remote Sensing and Geographic Information Systems (MCCRSGIS). Editing was concentrated along the coastline to ensure NHD hydro 
fell reasonably close to the imagery. Outside the coastline, there was sparse editing of the NHD. This was
for time constraints only. The ArcGIS topo-to-raster command was used to generate tiled 5 ft DEMS. The individual tiles for each county were mosaiced using the Mosaic-to-new-raster command with 32 bit floating and blend options.

For more information, contact Steve Walker at (601) 432-6149 or swalker@ihl.state.ms.us