Page 1 of 1

PostPosted: Sat Mar 27, 2010 3:35 pm
by Christian
this is a questions for the gurus (eg Robin & Timmo)

I have a few tiles of aerial photography which I'd like to bring into FSX. I needed to reproject and convert to GeoTiff, the problem I'm having is that I get black borders around the images (because of the reprojection the tiles are a bit slanted). I'd like to keep the tiled individual, so how do I get rid of the black border?

Also, I can't seem to open the GeoTiffs in Photoshop (the file is just black), which I need to create watermasks and the like. I converted the file via ArcMap, so Timmo you may know what the answer is...

Cheers,
Christian

PostPosted: Sat Mar 27, 2010 4:30 pm
by toprob
I always like to slice my images after reprojection, to overcome the problem with the reprojected corners. However you can get around this, by blend-masking the corners.

I don't know if it would be a good enough solution, but you could also use NullValue = 0,0,0 to remove the black bits, but of course this would remove anything black.

Here's my normal workflow, which may help provided Timmo can help you with the GeoTIFF-> PhotoShop problem:) -- I don't use PhotoShop, so I'm not much help there.

Once I get my image(s) reprojected I use 'GeoTIFF Tools GUI' to extract the Georef info. I can then treat all subsequent images -- the edited aerial, water and blend masks -- as normal TIFFs, and then use GeoTIFF Tools GUI to put the info back ready for Resampling. This is a very simple process.

PostPosted: Sat Mar 27, 2010 8:51 pm
by Christian
toprob wrote:
QUOTE (toprob @ Apr 1 2010, 04:30 AM) <{POST_SNAPBACK}>
I always like to slice my images after reprojection, to overcome the problem with the reprojected corners. However you can get around this, by blend-masking the corners.

I don't know if it would be a good enough solution, but you could also use NullValue = 0,0,0 to remove the black bits, but of course this would remove anything black.

Here's my normal workflow, which may help provided Timmo can help you with the GeoTIFF-> PhotoShop problem:) -- I don't use PhotoShop, so I'm not much help there.

Once I get my image(s) reprojected I use 'GeoTIFF Tools GUI' to extract the Georef info. I can then treat all subsequent images -- the edited aerial, water and blend masks -- as normal TIFFs, and then use GeoTIFF Tools GUI to put the info back ready for Resampling. This is a very simple process.


Thanks Robin. Tried the NullValue with no success. Blend masking is what I'd like to do, but my tifs come out black in any image editor. The work for resample which leaves me puzzled... I was planning on using a geotiff tool which stores the header info, but as long as I can't get the image to show in an editor, this is of course not going to work...

PostPosted: Sun Mar 28, 2010 9:27 am
by Christian
Ok, solved the problem. ArcMap exported 16bit Tifs that were showing black for some reason. Exporting 8bit seems to work fine. Weird.