Hi, it seems that my points are too many. I am waiting for the TIN process to finish (needs a few hours it seems), then I will select a part of the point I am interested in and go on working on that selection. Then I will try your suggestions, thank you.
Some other remarks: > You can also correct this 5x5 problem by using gdal grid with Nearest > neighbour interpolation. You could use the point data to do this. So the GDAL tools in the processing toolbox? > I also post a small presentation that can help go from vector to raster with > point data. Sometimes, keeping it simple is better. > > https://www.slideshare.net/shencoop/qgis-raster-to-point This is the other way round, but I could check that everything went right with my .xyz-Data and the creation of the point cloud. > If you do decide to make a shapefile with the csv, make sure to store the > coordinates in a text field. Placing the coordinates in a $x and $y object > fields will lead to rounding. Any rounding would corrupt the raster > therefore you need to original coordinates for this to work. This may explain > your problems also. I do not really understand, but I think when I try, I will see what you mean. > I used this method to change the geoids of a thousands of rasters because the > program I was using was designed to change the z value for texte files only > and not rasters (NRCAN GPS-H). Sounds good :-) I will report tomorrow again, and thanks for taking care, Maria > > Nicolas Cadieux > Ça va bien aller! > >> Le 13 mai 2020 à 11:25, chris hermansen <clherman...@gmail.com> a écrit : >> >> >> Maria and list, >> >> On Tue, May 12, 2020 at 7:00 PM Priv.-Doz. Dr. Maria Shinoto >> <maria.shin...@zaw.uni-heidelberg.de> wrote: >> Hi, >> >> Thanks for helping. -- Thanks to you and Chris Hermansen I got a result, but >> it could be better. >> >> For the records, a short explanation: >> >> ***** >> Well, I checked the properties, jgd2011 is in Meters, the raster is said to >> be 5m. In the official Japanese viewer, which creates a beautiful raster >> image without white pixels, the pixels are exactly 5m*5m. >> >> Today I tried the export to .xyz since the shapefile looked ugly, and after >> realising that the Japanese xyz is indeed yxz, everything looked fine, and I >> could store it in a Geopackage. But the grid is now 5,276m * 6,146m. But it >> fits well on top of the basemap. The basemap is of the same special Japanese >> GML format, but QGIS could read it all without problem. I do not understand >> why QGIS does not read the point data from the GML fille, but that is an >> aside, I am amazed by what QGIS actually can do. >> >> From the Geopackage I could rasterize. It is as Chris Hermansen said, >> thanks. Unfortunately, I did not get it done from the shapefiles, they >> always looked weird or like nothing, even with identical settings. But the >> geopackages from xyz tiles are fine. >> >> For resolution, I chose georeferenced units as Chris suggested, and since >> the measurement tool got some different length, I put it to 5,276m by >> 6,146m. A 5m by 5m resolution created a weird layer with horizontally >> expanding white pixels. >> >> It seems that tweaking with the resolution might lead to an even better >> result, but for the time being, it is OK as it is. >> ***** >> >> >> Upon reflection I think the basic problem here is that the point data should >> be interpolated to create a raster if you want a precise 5x5m resolution. >> >> For this, rather than use the Raster > Rasterize tool, the approach should >> be: >> • open the processing toolbox Processing > Toolbox >> • in the toolbox open Interpolation > TIN interpolation >> • in the TIN Interpolation screen: >> • select the Vector layer >> • select the Interpolation attribute >> • click the + to add to the vector layer panel >> • choose the interpolation method - probably best to use cubic >> • click on the ... next to extent and set it to the layer extent >> • set the pixel size to 5.0 and 5.0 >> • click Run >> This way you won't have the odd sizes you mentioned. This may give you a >> smoother surface in the end as well. >> >> >> -- >> Chris Hermansen · clhermansen "at" gmail "dot" com >> >> C'est ma façon de parler. _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
