I'm working on watershed hydrology, then I went to obtain drainage direction, accumulation zones, streams system and elementary watersheds of a study area. However I work on an area which belong to 2 EPSG (EPSG 3313 and EPSG 2972).
I download all the SRTM tiles of the study area and have filled the voids. I merged these tiles and projected the result in the EPSG 2972 (initially WGS84). Of course, a part of the DTM has negative EAST coordinates which cause errors when assinging region and running r.watershed and r.water.outlet.
I tryed to work in WGS84 but still r.water.outlet does not work.
Is it possible to define a region with two EPSG? How achieve r.water.outlet with success
I'm quite locked...Any help ?
------------------------------------------------------------------------------------
B.Mourad
Laboratoire de Mathématiques Informatique et Applications
Université de Guyane
Tél : 06 63 81 50 29
How far into the second UTM Zone does your region go? If not far and the
distortion is acceptable you can reproject 1 into the other.
Otherwise you need to find or create a Projection that does a better job
of covering your region. A UTM projection is unlikely to be a good
candidate in this case. Do you care more about preserving Area or
Distance measures (that will help you pick an appropriate projection).
So, no, you can not use 2 EPSG codes at the same time, you have to
convert the data into a common projection.
Thanks,
Alex
On 03/16/2016 08:10 AM, Mourad Boutouchent wrote:
I'm working on watershed hydrology, then I went to obtain drainage direction, accumulation zones, streams system and elementary watersheds of a study area. However I work on an area which belong to 2 EPSG (EPSG 3313 and EPSG 2972).
I download all the SRTM tiles of the study area and have filled the voids. I merged these tiles and projected the result in the EPSG 2972 (initially WGS84). Of course, a part of the DTM has negative EAST coordinates which cause errors when assinging region and running r.watershed and r.water.outlet.
I tryed to work in WGS84 but still r.water.outlet does not work.
Is it possible to define a region with two EPSG? How achieve r.water.outlet with success
I'm quite locked...Any help ?
------------------------------------------------------------------------------------
B.Mourad
Laboratoire de Mathématiques Informatique et Applications
Université de Guyane
Tél : 06 63 81 50 29
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