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Posted by Mississippi Dan on July 9, 2006, 6:04 pm
Please log in for more thread options Clipping works okay with smaller tiff files. You might be
able to tile the large mosiacs into 7.5 min size or smaller,
clip the ones along the boundary, then put the tiles back
together.
I tried the NW0401 on my computer for 4 hrs without
progress. A DRG from Missouri starts the progress bar in a
few moments and looks like it would take 15-20 minutes. I
lost power before the operation completed, then was out of
town for the weekend.
I'll try another software tonight or tomorrow.
Best,
Dan
> Dan,
>
> Thanks for the reply. I am working with geotiffs from
> here:
> http://casil.ucdavis.edu/casil/gis.ca.gov/drg/7.5_minute_series_albers_nad83_mosaic/tiff/
>
>
> As you can see from the index map, it takes more than one
> mosaic to cover a
> California county, for example, Sonoma, where I am from.
>
> The applicable mosaics for Sonoma are NW0502, NW0401-0402,
> and NW0301.
>
> Global Mapper can export a rectangle shaped map, clipping
> the mosaics above.
> However, I have not been able to get it to clip to a
> shapefile
> county boundary obtained from the California county map
> here:
> http://casil.ucdavis.edu/casil/boundaries/cnty24k/.
>
> I edit the state boundary map to derive an area for only
> Sonoma, and export
> it to a new shapefile for use as a mask over the composite
> county mosaic I
> produced earlier. Global Mapper hangs immediately.
>
> Any thoughts?
>
> Thanks
>
>
> "Mississippi Dan" <jdanATREMOVEsemoDOTNOTnet> wrote in
> message
>>
>> >I am working with USGS DRG mosaics for California
>> >downloaded from CASIL.
>> > I am trying to trim them using county boundary
>> > shapefiles.
>> > Global Mapper cannot seem to handle the job, apparently
>> > due to the size of
>> > the DRG's
>> > It immediately hangs at the start of the process.
>> >
>> Be sure you are clipping a tiff file, not a sid. I use
>> global mapper and have no problems clipping tiff files of
>> this size.
>>
>> Dan
>>
>>
>
>
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