[GRASSLIST:3345] Re: Correcting SRTM with MrSID images

[tatel at euskalnet.net]

----- Jatorrizko Mezua -----
Norengandik: "Bryan K. Wright" <bryan at ayesha.phys.Virginia.EDU>
Data: Astelehena, Maiatza 3, 2004 4:29 pm
Gaia: [GRASSLIST:3334] Re: Correcting SRTM with MrSID images 

> Hi folks,
> 
> tatel at euskalnet.net said:
> > Unfortunatelly I can't register SRTM and image data. After
> > reprojecting image from UTM-WGS84 to Lat_Lon-WGS84, it seems to 
> be a
> > shift of about 250-300 meters towards W in SRTM from image. More
> > confusingly, this 
> 
> 	I've also seen a shift of about 200 meters between MrSid-format
> DOQQs and the corresponding USGS DRG files.  The MrSid files were 
> decodedusing the Windows version of mrsiddecode, which produces a 
> tiff and a
> tfw file.  There were actually two oddities in the tfw files.  Here's
> a quote from an earlier message I posted to the list about this 
> problem:
> bryan at ayesha.phys.Virginia.EDU said:
> > 	Two oddities with the tfw files, though:  the fourth line of the 
> file> (cell size) ended up being a positive number, which r.in.tiff 
> didn't
> > like.  Adding a minus sign fixed the problem.  I also found that the
> > last line of the file (northing) was offset by 200 meters 
> relative to
> > the USGS topo maps I'm using.  These may just be problems with the
> > original sid/sdw files I happened to be using. 
> 
> 	Since then I've heard from a couple of other people who've
> noticed the same thing.
> 
> 	                                        Bryan
> -- 
>
===============================================================================
> Bryan Wright                |"If you take cranberries and stew them 
> like 
> Physics Department          | applesauce, they taste much more like 
> prunes 
> University of Virginia      | than rhubarb does."  --  Groucho 
> Charlottesville, VA  22901  |	                
> (434) 924-7218              |         bryan at virginia.edu
>
===============================================================================
> 
>