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Re: [udig-devel] tif render error. 
At 19:47 03/03/2008, Jody Garnett wrote:

We are going to have to experiment and see; as far as I know:
- GeoTIFF
- World + Image (with additional support of a "prj" file if you need to be exact about your coordinate reference system)
My basic vector map data (roads, locations, routes, etc) is all lat/lon based, and my map is therefore using WGS84.
And your data is also set for WGS84? ie if it has shapefiles that is what the .prj file says? If it is is PostGIS the SRID=4326 etc...
All the vector data is in PostGIS, with SRID=4326. We don't use any shapefiles, in general. 


The raster tiles I have come with files that look like this:

tf70ne.tfw:

0.635001270002540
0.000000000000000
0.000000000000000
-0.635001270002540
575000.317500635000000
309999.682499365000000

tf70ne.tab:

!table
!version 300
!charset WindowsLatin1

Definition Table
  File "TF70NE.TIF"
  Type "RASTER"
  (575000,305000) (0,7874) Label "Pt 1",
  (580000,305000) (7874,7874) Label "Pt 2",
  (580000,310000) (7874,0) Label "Pt 3",
  (575000,310000) (0,0) Label "Pt 4"
CoordSys Earth Projection 8, 79, "m", -2, 49, 0.9996012717, 400000, -100000 
  Units "m"
It looks to me like you are mixing two things: GeoTIFF (where the details are encoded in the tiff file) and world plus image; where the details are defined in files with the same base filename as the tiff.
Hmm. How can I tell whether the tiff files have the geographic details encoded? My colleague who was looking at this told me that nothing at all worked until he got hold of the tfw/tab files from OS.
Can you make yourself a ".prj" file using the Well Known Text available on the advanced tab of the CoordinateReferneceSystem dialog in uDig?
Can you explain more precisely what I have to do, and then I expect I can do that.
Unfortunately when I import one of these images and add it to my map, it isn't placed anywhere near the other data, because it seems to be using coordinates (British National Grid?) in the range 575000, 305000.
I see that number (575000) in both your tfw file and your definition table? Are you defining the range of three axis? Or only two ...
I'm not really sure. These are all just standard OS data, and I'm just trying to use it.
On a related note, there are about a thousand of these tiles. How can I add them to the map in one go (and have them shown in the uDig user interface as one entity) rather than as a thousand separate layers in the map.
On trunk I have support for "Image Moasic" basically a shapefile with each record indicating what "tile" goes there .. that is the "right" way to do things; and I am afraid it is not available in 1.1.x.
Is it worth me testing out trunk? Or is that just going to hit a bunch of other issues? (is there a trunk sdk available for testing with?) 

regards,
Vince.

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