Expose visualization options in filter tuning app

[dokempf]

Currently, the visualization used in the filter tuning app cannot be configured, but really should be. This should probably be realized by a separate visualization schema which can directly be plugged into WidgetForm.

[mariashinoto]

Regarding my comments yesterday, I looked up the problem and found this solution in an email from myself to the QGIS mailing list:

Le 16 mai 2020 à 06:13, Priv.-Doz. Dr. Maria Shinoto maria.shinoto@zaw.uni-heidelberg.de a écrit :

After all it turns out that it is something Nicolas wrote, it is a matter of the projection. The Japanese software just exported to a projected format, but the original data seem to be in lat long. I found a way to get the unprojected data and now can create a beautiful hillshade in an unprojected lat long layer. And it even looks good in a projected project (EPSG:6670) with on the fly projection.

For hydrological analyses I need to use the projected data, but the artifacts do not matter here. While binge-watching YouTube videos I realized that these artifacts occur with the pros as well when they use the projected layers for their analyses. Now everything much better and "in place".

The problem discription is in the PDF I enclose together with visual examples of the problems. Maybe, this problem was rooted in the data set (grid, old projection) from the Japanese government?

Re- [Qgis-user] vector point grid to raster grid -- pixel size does not work.pdf

These two websites are those that helped me most.

• https://gis.stackexchange.com/questions/95337/scale-and-z-factor-have-no-effect-on-hillshade-analysis-in-qgis
• https://www.esri.com/arcgis-blog/products/product/imagery/setting-the-z-factor-parameter-correctly/

Please inform me if this is unnecessary information.

[dokempf]

Thanks for looking this up. To me, it seems like this is not directly related (as suspected yesterday). Still, it is valueable to have this information noted here as we have already been tripping over projection-related issues. We resorted to reproject all input to a unified reference system (EPSG:4326), but I have to admit that I have no full overview of the consequences.

[mariashinoto]

EPSG:4326 seems most globally applicable to me. We use EPSG:6670 for our area in South Japan, but there is no problem with on the fly transformations to other systems -- in QGIS at least. Bernhard should know best...