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IMG2PNG, PDS/FITS to PNG conversion
neo56
post Oct 26 2016, 01:53 PM
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Bjorn, are you developing or do you plan to develop a version of IMG2PNG for Mac ? That would be awesome.


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scalbers
post Dec 3 2016, 11:48 PM
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I'm checking how well GDAL works on a Mac to convert IMG files, at least in a rudimentary manner. I am able to do this with some files from a USGS Earth topography database. I wonder if their IMG format is the same thing as in the PDS?


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Rick Ramirez
post Feb 23 2017, 02:49 AM
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I've been having some trouble getting the results I expect from IMG2PNG. It's probably user error but I'm wondering if someone can help me. I'm trying to create a full 16-bit displacement map for the moon. The Tiff files available here (http://wms.lroc.asu.edu/lroc/view_rdr/WAC_GLD100) are only 8 bit. I've downloaded all of the .img PDS files to try and produce correct 16-bit images but I'm having no luck. Running the converter tells me that sample_bits=16 but the PNG file produced is severely clipped. The resulting PNGs have black and white data ranging from 0 to about 0.05. I've tried using -fneg and also playing around with -fStretch without much luck. These are processed LROC images so I didn't think I needed any kind of calibration files. Am I incorrect? If anyone has any clues, I would very much appreciate it.
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JohnVV
post Feb 23 2017, 06:22 AM
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the pds img files are here
http://lroc.sese.asu.edu/data/LRO-L-LROC-5...SDP/WAC_GLD100/

the img is a 16 bit SIGNED integer
gdal can convert a img to a tiff ( geo tiff)
example :
CODE
gdal_translate WAC_GLD100_E000N1800_016P.IMG WAC_GLD100_E000N1800_016P.IMG.tiff

a screenshot from Nip2 image editor


a height map heeds to be at least 16 bit depth or 32 bit float
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elakdawalla
post Feb 23 2017, 06:22 PM
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QUOTE (Rick Ramirez @ Feb 22 2017, 06:49 PM) *
I've been having some trouble getting the results I expect from IMG2PNG. It's probably user error but I'm wondering if someone can help me. I'm trying to create a full 16-bit displacement map for the moon. The Tiff files available here (http://wms.lroc.asu.edu/lroc/view_rdr/WAC_GLD100) are only 8 bit. I've downloaded all of the .img PDS files to try and produce correct 16-bit images but I'm having no luck. Running the converter tells me that sample_bits=16 but the PNG file produced is severely clipped. The resulting PNGs have black and white data ranging from 0 to about 0.05. I've tried using -fneg and also playing around with -fStretch without much luck. These are processed LROC images so I didn't think I needed any kind of calibration files. Am I incorrect? If anyone has any clues, I would very much appreciate it.


Have you tried the -s switch (like -s1024) to multiply all the pixels by a number?




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JohnVV
post Feb 23 2017, 08:30 PM
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the clipping is do to the img file being a SIGNED!!! integer in meters above and BELOW!!! "sea level"

that is -8967 METERS to a + 10714 Meters

using a multiplier will NOT put this into a unsigned range

16 bit signed pixel values ( -32768 to +32767 )
16 bit UNsigned pixel values ( 0 to 65538 )

you can use math functions
SUBTRACT the negative minimal value ( or add the min. absolute value ) to the image
an example using the G'mic image lib
CODE

gmic WAC_GLD100_E000N1800_016P.IMG.tiff -add 8967 -o WAC_GLD100_E000N1800_016P.16U.tiff,ushort
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elakdawalla
post Feb 23 2017, 09:03 PM
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Ah, right. I don't know that IMG2PNG currently handles signed data. But Bjorn is always tinkering with it so it's possible it could do so in the future.


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Rick Ramirez
post Feb 24 2017, 05:50 PM
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Thanks for the help. I didn't realize IMG2PNG could not handle negative values. I haven't used GDAL of GMIC but I'll check them out.
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Bjorn Jonsson
post Mar 6 2017, 11:14 PM
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I took a look at this and it's a bug in IMG2PNG that should soon be fixed. The problem is that 'normal' images usually do not contain signed data (and therefore no negative values) but this is a DEM and DEMs obviously can contain negative values. IMG2PNG recognizes some files as DEMs and handles them correctly but this DEM is 'unknown' to IMG2PNG. I'll probably add a new command line parameter to make it possible to tell IMG2PNG that the input file is a DEM in case IMG2PNG doesn't correctly recognize it as a DEM.
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Bjorn Jonsson
post May 1 2017, 03:48 PM
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QUOTE (Rick Ramirez @ Feb 23 2017, 02:49 AM) *
I've been having some trouble getting the results I expect from IMG2PNG. It's probably user error but I'm wondering if someone can help me. I'm trying to create a full 16-bit displacement map for the moon. The Tiff files available here (http://wms.lroc.asu.edu/lroc/view_rdr/WAC_GLD100) are only 8 bit. I've downloaded all of the .img PDS files to try and produce correct 16-bit images but I'm having no luck. Running the converter tells me that sample_bits=16 but the PNG file produced is severely clipped. The resulting PNGs have black and white data ranging from 0 to about 0.05. I've tried using -fneg and also playing around with -fStretch without much luck. These are processed LROC images so I didn't think I needed any kind of calibration files. Am I incorrect? If anyone has any clues, I would very much appreciate it.

This has now been fixed and a new IMG2PNG version is now available. I added a new command line option (-force_dem) which forces IMG2PNG to treat the input file(s) as a DEM if possible (the sample type must be signed which is the case for all of the DEMs I've seen).

IMG2PNG is available here:

http://bjj.mmedia.is/utils/img2png/index.html
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Bjorn Jonsson
post May 3 2017, 12:24 AM
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It has come to my attention that for some reason the upload of the new IMG2PNG version mentioned in the preceding post didn't succeed - the old version did not get replaced. So if you have downloaded the new version above to get the improved DEM handling you need to do so again - I have verified that this time the upload succeeded. Sorry for the inconvenience.

The new version should output this when you run it:

IMG2PNG v2.35 20170501
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Suchandler96
post Jul 3 2017, 04:32 AM
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I am recently handling the viking orbiter raw images, and in some images there are so many vertical missing lines that they are almost unreadable. I have found a software which can be found at
http://petermasek.tripod.com/viking.html .
Not only can it eliminate the vertical missing lines, it also removes some white speckles that appear in some VO images and performs contrast stretch. But the software can only process one image at a time, which makes it extremely inconvenient.
I would love IMG2PNG to include some of these features of this software(if possible)!
Attached thumbnail(s)
Attached Image
Attached Image
Attached Image
Attached Image

 
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jhagen
post Jul 3 2017, 07:12 PM
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QUOTE (scalbers @ Dec 3 2016, 03:48 PM) *
I'm checking how well GDAL works on a Mac to convert IMG files, at least in a rudimentary manner. I am able to do this with some files from a USGS Earth topography database. I wonder if their IMG format is the same thing as in the PDS?



I've struggled with converting IMG files on my MAC, too. In the course of my experimenting with HiRise files, I stumbled on the fact that I can load IMG files directly into FITS Liberator. For anyone not familiar with it, this is readily available freeware. I have been using it for years to do initial histogram stretch on my astro-photography FITS files. Turns out it does what I need for IMG conversion very smoothly. I convert the fairly large HiRise 32 bit DTM files into 16 or 32 bit TIF files to work with in other software. FITS Liberator has a variety of non-linear histogram stretch options. For DTMs I do a linear stretch using the black and white point samplers.

I'm not sure that this meets the needs folks are mentioning here, but it might be worth a try.
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