Thanks Jukka.
Good to know about gdalinfo -hist as you said the problem was the incorrect
setting for the nodata value.
I was using 32767 as suggested in various wikis, but instead now it works as
expected by changing the command to:
gdal_contour -a elev -snodata "-32768" -i src.tif contour.shp
Tom Beddard subblue.com> writes:
>
>
> I do specify -i 20 in my scripts (that was a typo just in my original
email). Does it still work ok for you with an interval of 20 instead of 100?
I stopped the test because it was so slow and would probably stopped because
of too big shp filesize.
You m
I do specify -i 20 in my scripts (that was a typo just in my original email).
Does it still work ok for you with an interval of 20 instead of 100?
I’m actually doing more tests just now. I’ve found that gdal_contour is
significantly faster with a far smaller output shape file size if I first
r
Jukka Rahkonen mmmtike.fi> writes:
>
> Tom Beddard subblue.com> writes:
>
>
> > Can anyone else confirm this behaviour when extracting contours from
> merged SRTM tiles?
Can you check this command, it is perhaps not that you actually used:
gdal_contour -a elev -snodata 32767 -i uk-3785.tif
Tom Beddard subblue.com> writes:
> Can anyone else confirm this behaviour when extracting contours from
merged SRTM tiles?
Hi,
If you can send me a link to your two SRTM tiles then I can have a try. GDAL
told you the very reason for your trouble
ERROR 1: Failed to write shape object. File si
I did try without changing CRS before doing the contour extraction, still no
luck.
The strange thing is that a single SRTM tile might generate a contour shape
file of ~120MB and take just over a minute to process, however combining just
two tiles with gdal_merge.py and then running gdal_contour
Am 22.03.2014 18:59, schrieb Tom Beddard:
Are there any tricks to generating contours from merged files or is
it just going to be a case of scripting the generation of lots of
.shp contour files from each of the elevation tiles?
Thanks for any help, I’m still on the steep bit of the learning c
I’m having an issue generating a contour shape file with gdal_contour from a
source file that has been merged with gdal_merge.py
I can generate contours from a single unmerged source tif without problems, so
it seems something gdal_merge.py is doing is causing an issue.
This is my process:
I’
