[Mapserver-users] Projection Help

[Frank Warmerdam]

Paul VanDyke wrote:
> I'm sorry for not being too specific, but I didn't know what information
> was necessary.  Thank you for the questions.
> 
> Here's what I'm doing:
> 
> I acquired a .jpg satellite picture of Alaska that was 5202x4002 pixels.
> I cropped it to 1800x1162 pixels (to include only the relevant parts)
> and saved it as a 24-bit uncompress RGB .tif file

Paul,

Ug.  Does the original jpeg image have a .jpw worldfile associated with it?
If not, I would assume it is just a raw image at this point with no association
with a spatial location.  It isn't clear whether it is a raw (unrectified)
satellite image or not.

> The raster shows up a just a spec on the map, but thru the
> georeferencing process, I expand it to the proper proportions and then
> output a recitfied image.  I realize that this image is going to be very
> grainy when zoomed in, but it's just a birds eye view (a very high
> bird/satellite) of our island.

Through the "georeferencing process"?  I am not clear on what you mean by
that.

> The rectified .tif does not have a coordinate system defined for it yet
> as checked with the LISTGEO command.
> 
> Then I assign it a projection from within ArcCatalog by right-clicking
> and selecting properties; choosing the "Spacial Reference" tab and
> clicking Edit; I then choose Import and select one of the shape files
> that is on the map and import it's coordinate sytem, which happens to be
> NAD_1927_StatePlane_Alaska_5_FIPS_5005.

Do the shapefiles properly overlay the image within ArcGIS?

> When I look at my MapServer output, the raster is plotted south of the
> shapefile by a big stretch. I originally said 100 miles but I think it's
> probably more like 700 miles.  Changing the projection in my .map file
> from init=epsg:26705 to init=epsg:26735 make the map disappear entirely.
> One of the rasters that work is of type 26705, but the shapefile that
> I'm working with is 26735.

What does gdalinfo report about the TIFF file in question?

Best regards,
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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