Problem With .tiff files

[karingka]

Was experimenting more with photoscenery. Downloaded an geotiff image from USGS, when opened in WED color appears fine but when opened in GIMP to convert to png and resize colour appears faded and I get a strange message. Screenshots below. Any ideas??

Thanks,

Mateus

[chris k]

Whoa. Looks like it has an Alpha channel (transparency) that Gimp can't figure out.

Can you try a different editor? (i.e. just a viewer than can save into a different format?)

- CK.

[karingka]

Problem is Chris, when I open it it any viewer program that's what it looks like. Only normal in WED.

[chris k]

Yeah. Some kind of weird alpha channel going on.

ZIP it up and email it to me. I'll see if I can normalize it for you.

- CK.

[karingka]

Easier still, just go here:

http://viewer.nationalmap.gov/viewer/

Then, in the search box, type in "telluride"

Zoom over KTEX (telluride regional airport)

hit download data (top right)

select orthoimagery, it's the second option, the 13N

and download any of the tiles near KTEX.

Thanks a lot. If you succeed, just let me know what you did.

Thanks again

Edited June 10, 2012 by karingka

[chris k]

Cool.! Never new they updated their natioal viewer (was using the seamless server). This seems to have that data but in a better way of downloading.

Dloading now... will try it out and see what I can do.

- CK.

[chris k]

Ok, Very very weird.

The GeoTIFF is 50% transparent upon download. When I remove the Alpha, it shows white underneath (as expected) - which is why it looks nasty. I did do a direct 1:1 conversion into .PNG (keeping the alpha) using OSX Preview, and it looks nasty then in X-Plane, as both the ortho and the X-Plane standard imagery is showing through.

So.. not necessarily a GeoTIFF problem - it's more of a USGS data-has-a-50%-alpha-channel-through-it-which-is-messing-up-the-final-imagery.

Second shot - I tried the seamless server, and indeed it's the exact same imagery.. Alpha and everything... So no change from the National vs Seamless Server (same 1.0m imagery downloaded - however, Seamless gives me a nice option to cut the TIFFs into smaller chunks (roughly 1k by 2k).

So, this time I used GraphicConverter (OSX), and did a "remove alpha channel'. Worked perfectly. Saved as .PNG then converted 3 times into 1024x2048 and loaded into X-Plane. Muuuuuuch better now.

So, if you want, send me your .TIFF or .PNG w/Alpha, and I can remove it. If not, check around for a different image editor than GIMP to remove the Alpha and re-save in PNG w/no Alpha.

- CK.

Edited June 10, 2012 by chris k

[larjeet]

Matt try and open it with paint dot net if you havent got it you can download it for free here http://www.getpaint.net/

[karingka]

Guys,

I played around with some functions in GIMP and found a way to remove this "channel".

Thanks a lot for your advice!!

[JB_XUSA]

Bout to say, if this is better just copy the image over itself 3 or 4 times and then flatten the image. I seem to get real deep colors and its a little more controllable.

[Sgt R Lee Ermey]

Just curious how did you remove the alpha in the USGS photos in GIMP?  When I select the layer,  go to layer/transparency the option to remove the alpha channel is grayed out.  It seems that the USGS tiffs are already merged/flattened when I load them into any editor.  The only solution is to play with the levels and adjust the gamma to get a decent color,  but in this case the levels don't match up for each program  Therefore I can't use a preset template.

Edited January 16, 2013 by Sgt R Lee Ermey

[chris k]

Each USGS image may be different. Ive just noticed that many ship with a 50% alpha channel.

 

....others are just crappy original imagery.

 

FYI - GraphicConverter has a batch function... I can apply the same recolouration/gamma change/etc to a series of images in all the same fashion; to keep the colour/brightness consistency between tiles. Works well.

 

A highly recommended purchase:

 

http://www.lemkesoft.com/content/193/key-features.html

Edited January 16, 2013 by chris k

[ryancz]

I use USGS a lot.

The transparency is annoying, but easy to fix.

Layer-Transparency-Threshold Alpha (set to 0)

[Sgt R Lee Ermey]

I actually tried photoshop on another PC I and it does NOT say there is an alpha layer at all.  Nor GIMP.  Threshold Alpha is greyed out in GIMP, and in Photoshop it only has the usual RBG channels. 

 

When you download from the USGS how do you do it?  I get an email with a zip file.  Inside the zip is all sorts of information and meta data but I only copy the .tif file out of it and extract it to my scenery/tiles dir.   The tif files snap perfectly to the correct geocoded locations its just this dang color issue.   I actually did find within one orthophoto a change in color.  You could see when the plane came back a couple hours later and the shadows were different.  It happens to be right across one of the runways I'm working!

 

Its like they took pictures from a high altitude when it was smoggy out. 

 

Anyway thank you for your suggestions. 

[Colin S]

I actually tried photoshop on another PC I and it does NOT say there is an alpha layer at all.  Nor GIMP.  Threshold Alpha is greyed out in GIMP, and in Photoshop it only has the usual RBG channels. 

 

When you download from the USGS how do you do it?  I get an email with a zip file.  Inside the zip is all sorts of information and meta data but I only copy the .tif file out of it and extract it to my scenery/tiles dir.   The tif files snap perfectly to the correct geocoded locations its just this dang color issue.   I actually did find within one orthophoto a change in color.  You could see when the plane came back a couple hours later and the shadows were different.  It happens to be right across one of the runways I'm working!

 

Its like they took pictures from a high altitude when it was smoggy out. 

 

Anyway thank you for your suggestions. 

 

Just copy into a new file and erase the background.

[Sgt R Lee Ermey]

That does nothing to improve the photo quality.  Unfortunately I need to adjust the levels on each photo and then the gamma.  The effect is the colors,  greens more specifically get brighter, but that overall haze sort of disappears.  But also the whites tend to whitewash completely out including some of the brighter colored dirt.  Dirt I have to darken if I want to see the details of it.  So the trouble is getting the levels and colors and gamma all similar across all the photos at least in the same area. 

[Redfisher]

One thing you can try is to make a mosaic of your tiles in PS, then create some layer masks to help adjust hue, saturation, levels, etc.  Once you get the desired results, crop away.

[Sgt R Lee Ermey]

Awesome idea.   What I did is used the actions to automate the process of leveling and resizing and exporting etc.  But I'm not sure how the colors will come out.  Problem is as a start I have 30 or so images to load and photoshop bitches at me when I load 12 or more. 

[3TB]

I too was attempting to work with USGS ortho TIFF files downloaded directly from the map viewer. Each file is 15,000 pixels square. I'm not having alpha issues, but when I load them in WED 1.2 (beta) in order to snap them on their coordinates, WED crashes. Is this a memory issue, or a file issue. The former orthos downloaded via email from USGS worked in WED.

[chris k]

15k x 15k Imagery - youre going to run out of memory (WED is a 32bit app, so it suffers from the same out-of-RAM+VRAM issues that 32-bit X-Plane does).

 

Again, import, make draped poly, delete TIFF, save WED project.

 

Repeat until done. this way only 1 TIFF is loaded into RAM at a time; a bit tedious, but keeps 32-bit apps from blowing their RAM.

 

- CK

[Sgt R Lee Ermey]

I've got the 64 bit version of photoshop but yeah I'll convert them first and then try and level the colors. 

[Sgt R Lee Ermey]

Well nothing I do seems to get the colors right.  I've tried every combination.  I give up on this area its just poor photography.  I think they did it during a hazy day or something.  Not to mention its different sources so the whole area I want to cover is mixed all in. 

 

I do have a question though - if you slice up orthophotos in half will they lose their geocoding? I want to do at least some detailed photos for the airport area. 

 

Also for exclusions,  you should select "objects" if you don't want autogen right?

[Redfisher]

 

I do have a question though - if you slice up orthophotos in half will they lose their geocoding? I want to do at least some detailed photos for the airport area. 

 

Also for exclusions,  you should select "objects" if you don't want autogen right?

 

I use a program called Global Mapper to cut up the geotiff's and convert them to png's.  If you edit the geotiff's in PS, I "think" they lose their geodata.  There are other ways to edit geotiff's and have them retain their geo reference data.  Chris, I'm sure can shed some light on it.  I do know there's a plugin for PS that does all of that but it ain't cheap.   As to the question of exclusions, you are correct.

[Sgt R Lee Ermey]

Thanks,  looks like this isn't going to be easy... rarely is!

[Redfisher]

Thanks,  looks like this isn't going to be easy... rarely is!

 

Trust me, it gets easier.  Like I said, I'm sure there are some cheaper options out there.  I know that many use command line tools to edit data.  

 

What area are you working with?