>
> Message: 4
> Date: Sat, 3 Jan 2009 13:25:31 -0800 (PST)
> From: Hamish <[email protected]>
> Subject: Re: [GRASS-user] Re: GRASS-user] Help with reprojection
> To: [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=us-ascii
>
> Hamish wrote:
>
>> > - create a simple xy location
>> > (lat/lon location will not allow north > 90, and your image while
>> > still not geo-referenced will go to 8100)
>> > - run r.region to set n,s,e,w bounds to 90,-90,180,-180
>> > - run g.setproj to rejig the location into a lat/lon one.
>>
>
> umm, that might not work -- r.info will still know the map is XY even
> if the location is changed to lat/lon.
>
>
>> > - check resolution is correct (nicely "0:01:20") with r.info.
>> > - zoom to area of interest. you probably do not want to reproject
>> > entire planet. after zooming check resolution is preserved,
>> > (g.region -p, maybe with "g.region res=0:01:20 -a" after zoom to fix)
>> > and run "r.mapcalc cropmap=fullmap" to perform the crop.
>> >
>> > then from the lambert location run r.proj to pull the
>> > cropped image across.
>> >
>> > there are some examples of this process in the GRASS wiki,
>> > look at the "Global datasets" page.
>>
>
> the above issue should be covered there; also check the mailing list
> archives.
>
> so your "easiest" solution is to create a "world file". see the GDAL
> JPG or GeoTiff format import page, or do a web search for instructions.
>
>
> Hamish
>
Hamish,
Grass-6.3.0 under Mac doesn't seem to be checking for the world file.
My test:
1) Export a raster using r.out.tiff with the "create world file" box checked
2) Check the output folder:
test.tiff
test.tfw
3) Import using r.in.gdal:
r.in.gdal input=test.tiff output=test_2
In mine, this produces a projection mismatch error - which seems to tell me that Grass isn't noticing the tfw file.
Richard
