Opened 20 years ago

Closed 5 years ago

#511 closed enhancement (wontfix)

gdalwarp: suggestion for '-kr' (keep resolution) flag

Reported by: Markus Neteler Owned by: warmerdam
Priority: normal Milestone: closed_because_of_github_migration
Component: GDAL_Raster Version: svn-trunk
Severity: minor Keywords: gdalwarp
Cc:

Description (last modified by Markus Neteler)

Frank,

(as discussed via email)

It would be nice to have a flag in gdalwarp, e.g. called 
'-kr' (keep resolution) to maintain the original resolution of the warped
band. Of course there is -tr, but, say, for LANDSAT7 with 3 different 
resolutions (MODIS, ASTER etc the same), I have to check them manually
and then define them with -tr.

But with a '-kr' flag  I could simply loop over all channels in a shell
script and apply a datum transformation (so one step instead of
3 times resolution lookup + 3 times defining -tr).

Constraints: 
* Check that the units don't change, if yes, ignore (with warning) -kr flag
* others?

Best regards

 Markus Neteler

Change History (7)

comment:1 by neteler@…, 19 years ago

Frank,

on the list I have seen that you intend to revisit gdalwarp.
May I bring this (small?) wish to you attention, having
a flag to keep the original resolution when warping?

This would be most convenient for scripted looping over multiband
images of satellite data which come with different resolutions
(ASTER, LANDSAT, etc).

Best regards

 Markus

comment:2 by Markus Neteler, 15 years ago

Description: modified (diff)
Keywords: gdalwarp added
Version: unspecifiedsvn-trunk

The "magic" would skip this part:

trunk/gdal/alg/gdaltransformer.cpp@17302#L162

comment:3 by Jukka Rahkonen, 9 years ago

Does gdalwarp really support well or at all images which have different resolutions on separate bands? I do not remember why, but for sure I have been resampling Landsat scenes so that thermal bands have the same resolution than the thematic ones and Panchromatic band I have been moving to another file.

I have nothing against the -kr option, just thinking about how much it would really help.

in reply to:  3 comment:4 by Markus Neteler, 9 years ago

Replying to jratike80:

Does gdalwarp really support well or at all images which have different resolutions on separate bands?

Yes, of course.

I do not remember why, but for sure I have been resampling Landsat scenes so that thermal bands have the same resolution than the thematic ones

I would not do that. It is just a waste of disk space and useless processing time.

and Panchromatic band I have been moving to another file.

I have nothing against the -kr option, just thinking about how much it would really help.

A lot, as outlined in the original request.

comment:5 by Jukka Rahkonen, 9 years ago

Must have been a client side problem. I still seem to have loads of lossless JPEG2000 files with all the Landsat bands in native resolutions, also the thermal and panchromatic. They were quite tricky to process, that I remember very well.

If I remember right I could not finally find any JPEG2000 viewer that could show them in any reasonable way and MapServer could not handle them either. So we ended to have theoretically optimal copies in archive and all-bands-with-same-resolution copies for our real needs. Sort of waste of disk space and useless processing time, that too.

comment:6 by Even Rouault, 9 years ago

Priority: highnormal

All those tickets have more than one year and nobody has acted on it, so the priority is not so high

comment:7 by Even Rouault, 5 years ago

Milestone: closed_because_of_github_migration
Resolution: wontfix
Status: newclosed

This ticket has been automatically closed because Trac is no longer used for GDAL bug tracking, since the project has migrated to GitHub. If you believe this ticket is still valid, you may file it to https://github.com/OSGeo/gdal/issues if it is not already reported there.

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