* Tomáš Brunclík <[email protected]> [2015-05-29 13:34:22 +0200]: > Dne 27.5.2015 v 18:43 Nikos Alexandris napsal(a): > > * Tomáš Brunclík <[email protected]> [2015-05-27 12:49:13 +0200]: > > > >> Hello all, > >> working with GRASS GIS 7.0.1svn (r65198) @Linux, I noticed, that when > >> importing two Landsat images from different dates, I often get them > >> spatially shifted to each other when comparing them in detail - meaning > >> when you zoom in to about 1:5000 scale and switch the viewed bands, the > >> features in the map jump by a fraction of pixel size. For Landsat 8 > >> images LC81910252013208 (reflectance product) and LC81910252013224 (DN > >> product) the shift is about 15m (half the pixel size) in both horizontal > >> and vertical direction. The same two products imported in GRASS 6.4.4 > >> have no visible shift at all and the corresponding pixels seem to be > >> perfectly aligned. > >> > >> The procedure to reproduce this: > >> > >> 1)Download and uncompress this archive (133 MB): > >> https://dl.dropboxusercontent.com/u/24062833/pixel_shift_208_224.zip > >> / > >> The archive contains band 5 of the two above mentioned Landsat scenes, > >> where the one with DOY 208 (the last number of the scene code, > >> day-of-year) is from surface reflectance (SR) product, the other with > >> DOY 224 is digital number (DN) product (I work on a script to > >> atmospherically correct DN product based on reference SR image)//.// > >> / > >> > >> 2) Start GRASS 7, create new mapset in location with UTM 33N > >> (EPSG:32633) spatial reference system. > >> > >> 3) Import each image, open them in the map, set colors, zoom in and > >> compare a distinct feature placement in detail: > >> > >> #import > >> r.in.gdal input="/path/to/data/LC81910252013208LGN00_sr_band5.tif" > >> output=208_grass7 > >> r.in.gdal input="/path/to/data/LC81910252013224LGN00_B5.TIF" > >> output=224_grass7 > >> > >> #set the null pixels of the DN band (helps the bands to get similar > >> color palette in the next step) > >> r.null map=224_grass7 setnull=0 > >> > >> #set colors: > >> r.colors map=208_grass7 > >> r.colors map=224_grass7 > >> > >> > >> 4) Zoom in to a distinct feature in about 1:5000 scale (I have used a > >> pond at coordinates 542365,554675), switch visibility of both images on, > >> then repeatedly switch on/off the upper image in the stack. You should > >> see the shift quite clearly. Zooming in even more, it is possible to > >> measure the shift. > >> > > Tomas, > > > > I had a quick look. Pixels are perfectly aligned here (after going > > through all of the steps you mention here) in G7. > > > > Which version of GDAL are you on? > > > > Nikos > > > > [rest deleted]
Tomas: > Hello, > I have GDAL 1.6.3 in GRASS 7, GDAL 1.10.1 in GRASS 6. Could it be it? Is > the GDAL part of the binary snapshot download, or does it uses one > already on my system? My GRASS 7 is binary snapshot download, GRASS 6 is > installed from Debian packages coming from my distro repository. > Tried again with newly created location and mapset, the same result. > My GRASS 7 details: > Verze GRASSu: 7.0.1svn > Revize SVN GRASSu:: 65198 > Datum sestavení: 2015-05-09 > Platforma sestavení: x86_64-unknown-linux-gnu > GDAL/OGR: 1.6.3 > PROJ.4: 4.7.0 > GEOS: 3.2.0 > SQLite: 3.7.13 > Python: 2.7.5+ > wxPython: 3.0.1.1 > Platforma: Linux-3.11-2-amd64-x86_64-with-LinuxMint-1-debian > > My GRASS 6 details: > GRASS version: 6.4.4 > GRASS SVN Revision: > GDAL/OGR: 1.10.1 > PROJ4: Rel. 4.8.0, 6 March 2012 > Python: 2.7.5+ > wxPython: 3.0.1.1 > Platform: Linux-3.11-2-amd64-x86_64-with-LinuxMint-1-debian I can't tell for sure, unless we test it. Don't you have access to GRASS7 with latest GDAL? Couldn't you simply try the latest OSGeo-Live? Shouldn't take too much time to install virtualbox, get the virtual machine, and launch GRASS there. There is only some small number of steps to create a shared directory between host and guest. Anyone else on the matter? Cheers, Nikos _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
