[GRASS-user] Re: Import/conversion problem

[Stuart Edwards]

Glad you found a fix.  I'll have to remember this in case I have to venture north into MI.

It would be interesting to import the tifg into a new location in GRASS letting the image set the projection, and then reproject it from there into your project location with r.proj.  But I guess since it's a an issue with PROJ that you'd probably run into the same problem.

Stu



On Feb 11, 2011, at 5:40 PM, Adam Dershowitz, Ph.D., P.E. wrote:

> 
> 
> On Feb 11, 2011, at 9:23 AM, Adam Dershowitz, Ph.D., P.E. wrote:
> 
>> I am trying to import some data in GRASS and have run into a problem.  I hope someone can give me a little insight to help out.
>> I downloaded some aerial imagery from here:
>> http://www.michigan.gov/dnr/0,1607,7-153-10371_14546-30211--,00.html
>> 
>> I want to import it into a UTM zone 17 project.  So I did the following:
>> gdalwarp -t_srs '+proj=utm +zone=17 +datum=WGS84' input.sid output_utm.sid
>> 
> 
> 
> I googled around some and it looks like this is actually an issue with the Michigan projection in Proj4.  
> 
> I found this link:
> http://www.osgeo.org/pipermail/mapserver-users/2006-July/018292.html
> 
> And this seems to give reasonable results, based on the above:
> 
> gdalwarp -t_srs '+proj=utm +zone=17 +datum=WGS84' -s_srs '+proj=omerc +lat_0=45.309166667 +lonc=-86.0 +alpha=337.255555556 +k=0.9996 +x_0=499839.8337 +y_0=528600.2398 +ellps=GRS80 +datum=NAD83 +units=m' oakgrove_sw.sid oakgrove_sw_utm.tifg
> 
> 
> Then it imports into grass fine.  So, it seems like something is broken with that projection.
> 
> --Adam_______________________________________________
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