Re: [Qgis-user] Hillshade default direction
> Thank you to both of you for your informative responses. > This prompted me to look at some satellite imagery and while the > plateau vs. valley effect is not as distinct, the reversal of hills > persists. Never noticed that before. Off topic but it's something that has always bugged me about so many of NASA's images of the lunar surface. The lighting is so often from the bottom right of the image making them look like bumps instead of craters. For example this looks like it's covered in pimples to me rather than small craters: https://phys.org/news/2016-10-reveals-lunar-surface-features-younger.html I always assumed it was because I spent so much time on computers, where all the user-interface buttons are lit from the top-left. When you click a button to make it look like it's being pushed in, the border colours around the button change to make it look the same as if it was lit from the bottom-right instead (plus the text is moved a few pixels to add to the 3D effect). I wonder - does that mean everyone who is used to south-east lighting sees UI buttons as being pushed in by default, and they pop out when you click on them? Cheers, Adam. ___ 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
Re: [Qgis-user] Hillshade default direction
Thank you to both of you for your informative responses. This prompted me to look at some satellite imagery and while the plateau vs. valley effect is not as distinct, the reversal of hills persists. Never noticed that before. ___ 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
Re: [Qgis-user] Hillshade default direction
David Strip qgis-user at stripfamily.net Mon Jan 22 21:39:32 PST 2024 See also: - https://gis.stackexchange.com/questions/283546/hillshading-makes-crater-like-depressions-look-elevated/283635#283635 - https://pro.arcgis.com/en/pro-app/latest/tool-reference/3d-analyst/how-hillshade-works.htm - https://sci-hub.hkvisa.net/10.1126/science.194.4263.374 Best regards Andrea ___ 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
Re: [Qgis-user] Hillshade default direction
Hi David, On 23-01-2024 06:39, David Strip via QGIS-User wrote: After a lifetime of NW hillshades, my eye reverses hills and valleys when I shift the sun. This is not caused by looking at NW hillshades, but by looking at real life objects where light normally comes from above. This is what your brain is expecting and therefore it generates a 3D "bump map" for you that way. And that's why a GIS uses a sun position from the top of the map, often north. (Turning your SW map upside down should fix the problem.) Raymond ___ 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
