support for multi-page GeoTIFF (pre-)viewing would be wonderful!

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verbage
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support for multi-page GeoTIFF (pre-)viewing would be wonderful!

Post by verbage » Thu Jan 25, 2018 5:37 am

GeoTIFF is a TIFF-based format that is commonly used in GIS and remote sensing applications. Very often GeoTIFF format is used to provide quick browse preview images for the full data set associated with a multi-spectral/band scene. Why? Because the full data set associated with a multi-spectral/band scene can easily weigh in at 500+ MB. And such full data sets usually come packaged in archive formats like tar.gz or zip. So to simply get a quick glimpse of the scene, one would have to extract the bands of interest from an archive, and then merge them together. In sum, it's a huge hassle just to get a quick glimpse of the data; hence, the whole raison d'être behind such GeoTIFF quick browse preview images.

XnView can (pre-)view single-page GeoTIFF images perfectly, woo-hoo! But I've been dealing with multi-page GeoTIFF quick browse preview images from the ESA Sentinel-2 program (http://www.esa.int/Our_Activities/Obser ... Sentinel-2), and these give XnView a problem. XnView seems to get mixed up on the multi-page nature of these images, and does not render them correctly. NB--this is my interpretation of the problem, i.e. that the multi-page nature is causing a problem, but admittedly, this interpretation could be completely incorrect! For example, maybe the ESA just does something non-standard with their multi-page TIFFs, which causes a problem? I suggest this because in my own experience, XnView can deal with regular multi-page TIFFs with no problem.

Whatever the case, if future support for these multi-page GeoTIFFs--or at least the ESA-produced variants--were to be included in XnView, that would be a greatly appreciated feature (certainly by me, but probably by many others, too!).

Full specs about the GeoTIFF format can be found at http://trac.osgeo.org/geotiff/.

I can provide some of these ESA Sentinel-2 quick browse preview images in GeoTIFF format, too, if need be.

Thanks so much for considering this suggestion!

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xnview
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Re: support for multi-page GeoTIFF (pre-)viewing would be wonderful!

Post by xnview » Thu Jan 25, 2018 6:41 am

yes please send me some samples?
Pierre.

verbage
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Re: support for multi-page GeoTIFF (pre-)viewing would be wonderful!

Post by verbage » Thu Jan 25, 2018 5:04 pm

Hi Pierre,

Thanks so much for your response and potential interest.

I tried to attach some example images like you requested, but they are too big (one is about 6.5 MB). So I am just providing URLs instead.

https://earthexplorer.usgs.gov/browse/f ... 205T110426
https://earthexplorer.usgs.gov/browse/f ... 212T091748

Those links lead to two recent quick browse preview GeoTIFFs (one of Madrid and the other of west Crete). Each of these preview GeoTIFFs contains six different subpages of images, which are simply different resolution views of the same scene. They end up getting rendered as vertical strips down the the left side of the screen by XnView.

Like I mentioned, I think this is because they are multi-page GeoTIFFs because XnView seems to open single-page GeoTIFFs fine.

I am happy to provide any more details or information that you might need, and I thank you so much for all your efforts through the years with this wonderful piece of software!

verbage
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Re: support for multi-page GeoTIFF (pre-)viewing would be wonderful!

Post by verbage » Sun Jan 28, 2018 5:56 pm

Just an additional note here that does not really change the point of this thread, but I want to make sure that I am not spreading misinformation. I thought that these quick browse preview GeoTIFF images were produced by the ESA, but I now believe they are probably produced by the USGS.

I thought this because I get my Sentinel 2 data from the USGS, which mirrors it from the ESA. But a short while ago I visited the ESA's Copernicus Open Access Hub (https://scihub.copernicus.eu/) to verify that the USGS mirror was complete. And when I was there, I was puzzled to not see these GeoTIFFs (maybe I just missed them?).

So I went back to closely read the product description by the USGS (https://lta.cr.usgs.gov/sentinel_2), and saw a line that states "Full Resolution Browse (FRB) images in Georeferenced Tagged Image File Format (GeoTIFF) are also available from the USGS for Sentinel-2 tiles."

Since these GeoTIFF do not seem to be directly available from ESA (unless I missed them), that is why I now interpret them to be produced by the USGS.

As I mentioned, this observation does not really affect the whole point of this thread, but I just do not want to be spreading incorrect information about the source of these GeoTIFFS!

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Re: support for multi-page GeoTIFF (pre-)viewing would be wonderful!

Post by xnview » Mon Jan 29, 2018 9:17 am

ok, it's a Tiled TIFF, currently not supported by XnView. I'll check to support it
Pierre.

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