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<TITLE>Re: [UMN_MAPSERVER-USERS] latlong issues</TITLE>
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<FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>Chris -<BR>
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First, I think you’re using “geocodes” in an unusual way, and I’m not really sure what you mean by it. “Geocode” is a verb that means “take some data (like street addresses) and turn it into geographic coordinates (like lat/lon)”. The process is called geocoding. You’re using it as a noun and I really can’t figure out just what you mean. If you can give some examples that would be helpful.<BR>
<BR>
The EXTENT of your map must be specified in the units and coordinates of the output projection of your map image. While you can combine lat/lon data and UTM data in multiple layers, your output map image must be one projection. As I recall, you were taking a UTM source raster and producing a UTM output image. That’s fine. Do you want to change that? I would discourage you strongly from changing your output projection, as UTM is an excellent choice for your application.<BR>
<BR>
Your raster map image shows a certain portion of the world, at a certain resolution/scale, in a particular projection. Your world file documents this information so applications can use it. You can’t modify your image by playing with the world file – the world file either accurately describes the raster image, or it’s wrong. I think you had a correct world file for your raster layer already; if so, don’t touch it – you can only make it incorrect.<BR>
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If you can explain a little about what your geocodes are and how you need to display them we can probably help. If I’m missing the boat please try to explain what it is you’re trying to go (in non-technical terms).<BR>
<BR>
- Ed<BR>
<BR>
-- <BR>
Ed McNierney<BR>
Chief Mapmaker<BR>
Demand Media / TopoZone.com<BR>
73 Princeton Street, Suite 305<BR>
North Chelmsford, MA 01863<BR>
Phone: (978) 251-4242<BR>
Fax: (978) 251-1396<BR>
ed@topozone.com<BR>
<BR>
<BR>
<HR ALIGN=CENTER SIZE="3" WIDTH="95%"><B>From: </B>Christopher Harris <docterrobert@MSN.COM><BR>
<B>Reply-To: </B>Christopher Harris <docterrobert@MSN.COM><BR>
<B>Date: </B>Mon, 10 Sep 2007 11:44:06 -0500<BR>
<B>To: </B><MAPSERVER-USERS@LISTS.UMN.EDU><BR>
<B>Subject: </B>[UMN_MAPSERVER-USERS] latlong issues<BR>
<BR>
Hi. I posted last week about trying to get an image that I already have to be displayed on a layer with help from a world file. That all works. Now, I have new questions.<BR>
<BR>
My world file is using the UTM projection. The tricky part now is that I need to specify in my map file the extent in latitudes and longitudes. I have the appropriate geocodes, and I know that a world file and extent are lower left x,y then top right x,y and that an image is top left x,y then bottom right x,y. So I have all that compensated for, otherwise I wouldn't have gotten it working in meters for UTM as my extent. I've tried entering in the geocodes as the extent for the MAP object. That didn't work. So, I figured "I'm using UTM in my world file. Maybe I need to specify latlong projection for the MAP object." That didn't work either. I then tried adding that same projection to the one layer that I have. No luck. The image comes up blank once again. And yes, I've read the section on rasters.<BR>
<BR>
My questions:<BR>
How do I switch from using Meters as my extent to geocodes?<BR>
Do I need to use UTM for my world file? Every example I've seen on the net uses UTM. I've tried geocodes for the world file, but gdalinfo <image> indicates that the corner coordinates are totally off.<BR>
<BR>
The .php file is nothing special or elaborate. It just simply creates the image and draws it.<BR>
<BR>
My world file:<BR>
1<BR>
0.0000000000<BR>
0.0000000000<BR>
-1<BR>
393898.00<BR>
4438945.00<BR>
<BR>
My map file (I have the projections commented out as well as the EXTENT in METERS that worked)<BR>
MAP<BR>
NAME UniversityOfIllinois<BR>
STATUS ON<BR>
SIZE 1747 1916<BR>
IMAGETYPE GIF #image is 1747 X 1916 pixels<BR>
#PROJECTION<BR>
# "proj=latlong"<BR>
# "ellps=WGS84"<BR>
# "datum=NAD83"<BR>
#END<BR>
#EXTENT 393897.50 4437029.50 395644.50 4438945.50<BR>
#UNITS METERS<BR>
EXTENT 40.071888 -88.244698 40.094110 -88.217468<BR>
SHAPEPATH "/var/www/mapserver/basic/data/illinois/"<BR>
IMAGECOLOR 255 255 255<BR>
<BR>
OUTPUTFORMAT<BR>
NAME thegif<BR>
DRIVER "GD/GIF"<BR>
MIMETYPE "image/gif"<BR>
IMAGEMODE RGB<BR>
EXTENSION "gif"<BR>
END<BR>
OUTPUTFORMAT<BR>
NAME thepng<BR>
DRIVER "GD/PNG"<BR>
MIMETYPE "image/png"<BR>
IMAGEMODE PC256<BR>
EXTENSION "png"<BR>
END<BR>
<BR>
WEB<BR>
IMAGEPATH "/var/www/mapserver/basic/images/"<BR>
IMAGEURL "/mapserver/basic/images/"<BR>
END<BR>
<BR>
LAYER<BR>
NAME "UofI"<BR>
DATA "colorUofIllinois.gif"<BR>
TYPE RASTER<BR>
STATUS DEFAULT<BR>
#PROJECTION<BR>
# "proj=latlong"<BR>
# "ellps=WGS84"<BR>
# "datum=NAD83"<BR>
#END<BR>
END <BR>
END<BR>
<BR>
Any extra info needed:<BR>
MapServer version 4.10.0 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=THREADS SUPPORTS=GEOS INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG<BR>
<BR>
Any help would be spectacular. Thanks advance.<BR>
<BR>
- Chris<BR>
<BR>
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