Re: [gdal-dev] proper way to get area of a lon/lat polygon

2020-09-18 Thread Michael Patrick
> > ... but basically I came to the conclusion that when people talk about an > area of something on Earth they really mean the area of a projection (am i > right about that?) and so i need to specify a projection before getting a > meaningful area. So i ended up with this code: > > wkt = "POLYGON

Re: [gdal-dev] Slope obtained with GDAL has weird lines

2020-03-17 Thread Michael Patrick
orld you are, but if you tell me, I can probably make some suggestions. > *> Ah, let me guess. The dem grid was interpolated from contour lines and > you seeing the contours again.* > Can confirm, and they used a fairly crappy interpolation method also, it's not just terraced, i

Re: [gdal-dev] Extracting vector layers from Geospatial PDF

2019-02-06 Thread Michael Patrick
> > > This must be a redundant question but I really haven't figured out a way > to do this. I can export into a tiff but that's not desirable. > There are a variety of potential difficulties that can make this problematic. 1. PDF Version and compliance of the PDF file itself. 2. The lineage of th

Re: [gdal-dev] Proper algorithms for computing slopes for global/polar DEMs?

2015-02-22 Thread Michael Patrick
what scale you are interested, but there are a considerable number of others out there ( http://nsidc.org/data/dems/datasets.html ) Michael Patrick ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev

Re: [gdal-dev] Contour Gaps

2013-02-25 Thread Michael Patrick
al plane) etc. and how much automation and inspection you can tolerate. Do you have Z values for the contours? Or any common attribute which shares across the gaps? Michael Patrick ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osge