Hello, as some of you already know, the therionsurface2survex tool can generate surface meshes for aven out of therion surface or gdal grids. This allows for example to display a 3d-grid in loch and aven, and to take measures between cave and surface in aven. Today i enhanced the tool so it can understand the grid-flip command: https://github.com/hbeni/therionsurface2survex/issues/2#issuecomment-7877766... Also negative step size in gdal headers yield flipped grids. It would be cool if some people here could test it with real datasets :) The test case does what i would expect, but I’m not sure i fully understood the input data and its implications. Before i merge the feature, i would be much more confident by test results from more proficient people than me. Thanks and greetings! Beni