Ed,<br><br>This is the extent of my map: <br><br>EXTENT -3174450 -2816050 2867175 2406325<br>UNITS METERS<br><br>I'm trying to display a point element on a geotiff raster file, as follows (Note the decimal degree format):<br>
<br>LAYER <br> TYPE POINT<br> STATUS DEFAULT<br> FEATURE<br> POINTS <br> 56.5333333 -71.5 # <------- DD<br> END<br> TEXT "HELLO WORLD"<br> END<br> CLASS<br> COLOR 255 0 0
<br> SYMBOL 'cross'<br> LABEL<br> TYPE bitmap<br> END<br> END<br> TOLERANCE 5<br>END<br><br>The label, according to the coordinates given, sometimes appears, sometimes does not and most often
<br>on the same (erroneous) spot. <br><br>I tried to change the EXTENT (and UNITS) to decimal degrees according to the output of gdalinfo which outputs corner coordinates both in meters and decimal degrees. I thought I could this way make Mapserver understand I was specifying the input in decimal degrees so it should output correctly the point I want to draw. The scalebar also revealed seriously confused.
<br><br>I did not mention that the map is of Antarctica. This apparently complicates the matter since the EXTENT values are different than on most maps. <br><br>I'm new to this so I haven't got much knowledge about projections. The following two I have used successfully in displaying the map (but not the point):
<br><br>PROJECTION<br> "proj=stere"<br> "ellps=WGS84"<br> "datum=WGS84"<br> "lon_0=0"<br> "lat_0=-90"<br> "lat_ts=-71"<br> "units=m"<br>END<br><br>PROJECTION
<br> "init=esri:102021"<br>END<br><br>Thanks for your help,<br><br>Dan<br><br> <br><div><span class="gmail_quote">2006/5/5, Ed McNierney <<a href="mailto:ed@topozone.com">ed@topozone.com</a>>:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div style="direction: ltr;">
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2">D C -</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2">The UNITS and EXTENT in your mapfile need to correspond to
the units used in the projection of your data. If they don't, then you're
looking to reproject the data and there's some extra work you need to
do.</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2">gdalinfo will tell you the units and extent in the data
source's native projection. Changing those values in the mapfile won't
change the input data, and you're simply requesting an output image that doesn't
correspond to any part of your input data, so you (correctly) get nothing
displayed.</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2">What is it you're trying to do? Are you trying to
display the image in a different projection than the raster source image is
using? If so, what projection does the raster use and what output
projection do you want?</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span> <font color="#0000ff" face="Arial" size="2">- Ed</font></span></div>
<div dir="ltr" align="left"><span>
<p><font size="2">Ed McNierney<br>President and Chief Mapmaker<br>TopoZone.com /
Maps a la carte, Inc.<br>73 Princeton Street, Suite 305<br>North Chelmsford,
MA 01863<br><a href="mailto:ed@topozone.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">ed@topozone.com</a><br>(978) 251-4242 </font></p></span></div><br>
<div dir="ltr" align="left" lang="en-us">
<hr>
<font face="Tahoma" size="2"><b>From:</b> UMN MapServer Users List
[mailto:<a href="mailto:MAPSERVER-USERS@LISTS.UMN.EDU" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">MAPSERVER-USERS@LISTS.UMN.EDU</a>] <b>On Behalf Of </b>d c<br><b>Sent:</b>
Friday, May 05, 2006 5:54 AM<br><b>To:</b>
<a href="mailto:MAPSERVER-USERS@LISTS.UMN.EDU" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">MAPSERVER-USERS@LISTS.UMN.EDU</a><br><b>Subject:</b> [UMN_MAPSERVER-USERS] Raster
image doesn't show<br></font><br></div></div><div style="direction: ltr;"><span class="q" id="q_10b04e51c4c45d49_1">
<div></div>Hello,<br><br>I just changed the EXTENT of my mapfile which was in
METERS to DD.<br>I just wrote down the corresponding decimals which were given
by gdalinfo.<br><br>BEFORE<br>--------------<br>UNITS METERS<br>EXTENT -3174450
-3225675 2867175 2815950 <br><br><br>AFTER<br>-----------<br><br>UNITS
DD<br>EXTENT -131.5 -56.5 134 -52.3<br><br>nb: the map is a raster im. of
antarctica<br><br>The PROBLEM now is that THE MAP DOESN'T SHOW.<br>I don't get
an error or anything, the map just doesn't show. <br><br>Any suggestions?
<br><br>Thanks in advance. <br>
</span></div></blockquote></div><br>