[Mapserver-users] DTED Mapping Data

[James Anderson]

Hiya,

Thanks for the input.  The mapserver I am using is compiled with GDAL.  So
would I just setup it up like a normal raster layer ?  How to I go about
georeferencing it ?  Would I use a world file like with .png files ??  Is
there any chance you could give an example of mapserver layer setup ?

Thanks,

James.


----- Original Message ----- 
From: "Frank Warmerdam" <warmerdam at pobox.com>
To: "James Anderson" <james at danisat.net>
Cc: <mapserver-users at lists.gis.umn.edu>
Sent: Thursday, December 11, 2003 4:09 PM
Subject: Re: [Mapserver-users] DTED Mapping Data


| James Anderson wrote:
| >
| > Hello,
| >
| > I have a big problem.   I have been sent a lot of DTED data, extention
| > .dt1, also some .cov files.   I have since found out that this is U. S.
| > Department of Defense Digital Terrain Elevation Data, which is some sort
| > of three dimensional spacial data.  I have no idea how I am supposed to
| > convert this data or get it to work with the mapserver.  Currently this
| > does not look good, and I am under a lot of pressure from my work to
| > produce something with it.
| >
| > Currently I need the data to work in Mapserver.   I also have Mapinfo
| > professional 6.5 which I could perhaps use for something, but it does
| > not seem to support .dt1 data.  If there is a way to convert this data
| > to tab or shape files, or for mapserver to work with it directly, then I
| > would be very very very happy.
|
| James,
|
| DTED is a raster format, and is currently supported by GDAL if you have
| a mapserver build with GDAL support.  But the data is 16bit, not 8bit, so
| you will need to use some scaling to 8bit for visualization.  Adding a
| PROCESSING "SCALE=AUTO" declaration is likely sufficient to start though
| you might want to review the section on scaling at some point.
|
| However, you indicated an interest in converting the data to tab or
| shapefiles.  This leads me to suspect you want to see contours or
something
| similar.  If so, you will need to do some pre-processing.  The development
| version of GDAL includes a new utility for producing contour vector data
from
| elevation data that might be of some use.  Lots of other packages can do
| similar things.
|
| Note, if you have many DTED files, it likely makes sense to use a tile
index
| for them so you can treat them all as one layer.  If you do this, using
| fixed scaling likely makes more sense otherwise different scaling may be
used
| for different source files displayed in the same map view which would be
| confusing.
|
| Best regards,
|
| -- 
| ---------------------------------------+----------------------------------
----
| I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
| light and sound - activate the windows | http://pobox.com/~warmerdam
| and watch the world go round - Rush    | Geospatial Programmer for Rent
|