TIFF Files out of Photoshop?

[snah]

I want to get a bit of land scape that is inbetween 2 squares from the GEOTiff site, so i need to basically get 2 of the squares and join them together and then cut off the sides.

I opened them in photoshop and did the above procedure and then saved them back out as TIF files just like the originals... But L3DT errors with this:

CL3DTio_TIFF::LoadMapFile warning:
- unsupported GTModelType

CL3DTio_TIFF::LoadMapFile error
- cannot seek to strip

CExtDLL::LoadMapFile error
- call to DLL function 'LoadMapFile' failed

CMapGroup::LoadMapFile2 error
- error loading file

CMapGroup::HF_ImportFromFile error:
- call to LoadMapFile failed

Any help would be great! Thanks.

[Rummy]

Opening a Geotiff in Photoshop and resaving it nukes the header which contains all the geospatial information. There are expensive plugins you can purchase but I personally prefer to use VTBuilder from Virtual Terrain Projects to combine and resample dem or tifs...and I have programs like Arcmap.

[Aaron]

Hi Snah,

Thanks for the error report. I'll have a look into the support for TIFFs from PS. However, as Rummy noted, it's best co combine GeoTIFFs in programs that support GeoTIFF headers.

By the way, you can combine the maps in L3DT directly. To do this, import the first TIFF as normal, then use the 'Extensions->atMergeMap->Merge heightmap' menu option to add the second map with an offset (see user guide here).

To trim the map, you can use the select area tool to select the area you wish to keep, then export the selected area as a file (as HFZ, I suggest). Finally, simply load that exported area as your heightfield ('File->Import->Heightfield').

Cheerio,
Aaron.

PS: I just noticed that the merge heightmap option doesn't include the '.tif' extension in the filter for the file browser dialog box, so you'll have to select 'All files (*.*)' to see the TIFFs. This has been fixed in the next release. Also, in the next release the merge heightmaps menu link will be available at 'File->Import->Merge heightmaps'.

[Aaron]

Hi Snah,

I've fixed the GeoTIFF plugin so that it should now be able to read TIFF files that don't have GeoTIFF header data, such as those saved by PhotoShop. The updated plugin will be included in the next developmental build of L3DT.

Cheerio,
Aaron.

[Rummy]

That's good to know that I can combine in L3dt. Can we export tifs?

[snah]

Cheers both of you for the quick and helpful feed back, ill try and get my hands on some software that supports GEOTiff then i guess, but in the mean time ill just use Aarons method.


x

[Aaron]

Hi Rummy,

Sorry, the TIFF plugin doesn't support exporting just yet. I want to ensure the import support is rock-solid before I move on to writing files, just to be sure that I know all the configurations I'll need to support (TIFF = Thousands of Incompatible File Formats, or so I'm told )

Cheerio,
Aaron.

[Aaron]

Hi Snah,

On the downloads page is a new developmental build of L3DT (v2.7 build 17) that should make this map stitching and clipping process more straight-forward. The process should go something like this:

1. Import the first tile (GeoTIFF or otherwise) as per normal using the 'File->Import->Heightfield' option.
2. Import any additional tiles using the 'File->Import->Merge heightmap' menu option (userguide is here).
3. To clip the heightmap, first choose the 'select area tool' button from the toolbar, then click-and-drag to select the area of the map that you want to keep. Alternatively, you can use the 'Edit->Select area' menu option to specify the coordinates of the rectangle to be selected.
4. Press CTRL+C to copy the selected area to L3DT's clipboard.
5. Select the 'Edit->Paste as new layer' menu option. In the 'Enter layer name' pop-up window, set the layer name to "HF". This will overwrite the project's heightfield with the area that you selected.

You can now proceed with whatever further actions in L3DT that please you best (texture generation, export, etc.)

Please let me know if you find any problems.

Cheerio,
Aaron.