Re: [gdal-dev] Aster tif files to hgt

Jaromír Mikeš mira.mikes at seznam.cz
Wed Nov 9 21:31:03 EST 2011


> Od: Scott Arko <saarko at alaska.edu>

Hello Scott,

> I wouldn't worry about it the files look identical and the file is working
> in your application.  If you have a program that can load both formats you
> should be able to do a direct comparison to see if there is a shift. 

Actually I don't have a program to compare GeoTIFF and my hgt file at the moment.
 
> At most, it sounds like the shift you would encounter is 1/2 pixel or about 15
> meters.  

15m is not issue for me. I haven't idea how big shift it can be.

>I would try the files in your application and see if the results
> look reasonable.

I made comparison between map build from original SRTM files and map build from files I converted from Aster.

Aster based map

pros
* there are not holes at all for my area.

cons
* there are contours in sea ( they are not on original SRTM) 20m 40m.
there is not too much places like this, but they are.
* there are peaks in some areas which shouldn't be there 
they are on places where SRTM having holes, but some most SRTM holes are covered well by ASTER
Some of the peaks are over 4000m but there is highest point about 2600m in this area. 

---------------------------------

Is it possible remove at least some of these artifacts?
e.g. setting threshold for highest point on map?

regards

mira


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