Yes, I checked them visually for both raster and vector. I compared the results also visually. The rasters are transformed in a way that the end ponts of the gcp's align exactly with the result so that is why I referred to it as "right". The vector data result is in the neighbourhood of the end points (sometimes a rather significant distance).
The result is different from order 1-3 transformations so I presume the tps option isn't ignored. Stijn Op wo 16 aug 2023 om 11:52 schreef Rahkonen Jukka < jukka.rahko...@maanmittauslaitos.fi>: > Hi, > > > > Did you check the ground control points? What is your reference when you > say that one result is right, and another wrong? Have you used some other > software for comparison? Or do you only know that the results are different? > > > > -Jukka- > > > > *Lähettäjä:* Stijn Tallir <st...@strict.be> > *Lähetetty:* keskiviikko 16. elokuuta 2023 12.27 > *Vastaanottaja:* Rahkonen Jukka <jukka.rahko...@maanmittauslaitos.fi> > *Kopio:* gdal-dev@lists.osgeo.org > *Aihe:* Re: [gdal-dev] tps - gdalwarp vs ogr2ogr > > > > Hi Jukka, > > > > I thought of the density as an option for the "error" as you suggested and > I made a point-file with a point for every pixel in my original image and > used this as a source for the ogr2ogr transformation. So you could say the > desnity for both sources raster and vector) are then alike. > > > > The results were still the same (and wrong) ... > > > > Stijn > > > > > > Op wo 16 aug 2023 om 10:22 schreef Rahkonen Jukka < > jukka.rahko...@maanmittauslaitos.fi>: > > Hi, > > > > Without test data it is very hard to say much. I believe that the promise > of tps is that the ground control points stay where they are set. The > intermediate points follow the least tension surfaces and I do not know how > exactly those spline algorithms are defined. Raster data is full of points > to warp but probably in the vector data the transformation is done vertex > by vertex. I would first check if the GCPs are in the same place in both > outputs. Then I would make a test by densifying the vector data before > georeferencing to have much more vertices and see if it has any effect on > the result. > > > > -Jukka Rahkonen- > > > > *Lähettäjä:* gdal-dev <gdal-dev-boun...@lists.osgeo.org> *Puolesta *Stijn > Tallir > *Lähetetty:* keskiviikko 16. elokuuta 2023 10.29 > *Vastaanottaja:* gdal-dev@lists.osgeo.org > *Aihe:* [gdal-dev] tps - gdalwarp vs ogr2ogr > > > > Hi, > > > > According to the documentation gdal and ogr use the same algorithm for the > tps-transformation but I don't seem to get the same results using the same > set of gcp's for images and vectors. > > > > I have images that are unreferenced and vector data digitised on these > images (in pixel coordinates). > > > > The images are then georeferenced with +100 gcp's and warped with gdalwarp > using the "tps" option. > > > > When I use the same gcp's (with adjusted y-origin to lower left corner) to > georeference the vector data with ogr2ogr and the "tps" option I get > different results. The vector-result is similar to the image-result but > never exactly the same and differences can be substantial. > > > > Any thoughts? > > > > Stijn > > > > > -- > > Stijn Tallir - StrICT BV > > > > Wijnveld 8 > > 9112 Sinaai-Waas > > > > GSM: 0486 750220 > > > > E-mail: i...@strict.be > > Web: www.strict.be > > > > BTW: BE 0567.559.668 > > > >
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