Re: [gdal-dev] Transforming Raster Points from GeoTIFF with GCPs

2021-12-10 Thread Yann-Sebastien Tremblay-Johnston
Simon, See the Transformer API, in particular https://gdal.org/api/gdal_alg.html?highlight=transformer#_CPPv419GDALTransformerFunc (or gdal.Transformer in Python). Sebastien On Fri, Dec 10, 2021 at 10:24 AM Simon Eves wrote: > So we have a GeoTiFF of Sentinel-1 imagery which `gdalinfo` reports

[gdal-dev] Clarifying AxisMappingStrategy for SpatialReference read from GeoJSON in gdal > 3

2020-04-28 Thread Yann-Sebastien Tremblay-Johnston
Hi, Tested using conda gdal 3.0.4 and gdal bundled with QGIS (3.0.4) >From the documented changes in gdal > 3 with respect to honouring coordinate order i.e. lat/lon order for EPSG:4326, I would expect that when from osgeo import ogr > ds = ogr.Open('test.geojson') > layer = ds.GetLayer() > srs

Re: [gdal-dev] Interpolation used for egm96_15.gtx when using RPC_DEM_APPLY_VDATUM_SHIFT

2020-04-17 Thread Yann-Sebastien Tremblay-Johnston
Hi Even, To start with, you need the the dataset pointed by RPC_DEM is a compoundCRS > with a vertical CRS properly defined Thanks, I initially didn't understand why this wasn't working as the SRTM DEM I am using does not have a compoundCRS. I worked around this by creating a VRT with the correc

[gdal-dev] Interpolation used for egm96_15.gtx when using RPC_DEM_APPLY_VDATUM_SHIFT

2020-04-17 Thread Yann-Sebastien Tremblay-Johnston
Hi, I spent a bit of time learning about vertical datum shifts when performing RPC coordinate transformations using a DEM this week, and I was curious about how the egm96_15.gtx file is interpolated. I was able to find in gdal_rpc.cpp that the required vdatum shift is calculated using an OGR Coo