[udig-devel] tif render error.

[Vince Darley]

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.