Hi, The Swiss Statistical Office curates well-known datasets informally called "Hectare Raster" (STATPOP and STATENT) which obviously are ASCII Gridded XYZ, like this:
"RELI" "X" "Y" "C1" "C2" "C3" 66192542 661900 254200 1 2 3 ... 66192543 661900 254300 1 2 3 ... 66192599 661900 259900 1 2 3 ... 66192600 661900 260000 1 2 3 ... ... This obviously is a regular gridded X and Y, sorted by X,Y but obviously also has gaps and more than one "Z" (C1, C2, C3). Typically this is converted to a raster format like GeoTIFF and analysed through map algebra. Question 1: The GDAL docs (https://www.gdal.org/frmt_xyz.html ) says "...no missing value is supported.". In fact, I think it supports them by omitting lines by setting missing "lines" to NODATA. => Correct? Question 2: I think, there is a way (which could be mentioned in the docs above), to determine the "Z" value to be converted by gdal_grid explained in "Reading comma separated values" (https://www.gdal.org/gdal_grid.html#gdal_grid_csv ). So XYZ in fact is XYZx meaning that potentially there can be many "Z" in the input file, but only one can be included. => What do you think? Question 3 (the fundamental one): Although XYZ format requires to contain regular gridded coordinates, it's technically handled the same as irregular coordinates (without interpolation) - at least regarding the main task to convert an sparse array of values to a raster format. => Correct? :Stefan _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
