Run peak prominence / topographic isolation algorithm to display only prominent mountain peaks #9190

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opened 2024-09-01 15:01:04 +00:00 by hiddewie · 0 comments

hiddewie commented

2024-09-01 15:01:04 +00:00

(Migrated from github.com)

Is your feature request related to a problem? Please describe.

Currently, mountain peaks are shown from the first zoom level where downloaded country details are shown.

Every mountain peak is shown on the map, irrespective of its elevation.

(see screenshot)

Having fewer but more important mountain peaks on the map ensures the map is less cluttered, and more targeted. Especially together with contour lines, this creates a nice overview visualization of a region for the lower zoom levels.

The main OSM carto visualization has the same problem, see https://github.com/gravitystorm/openstreetmap-carto/issues/3722. However, that data has to be updatable dynamically without reprocessing the entire world when a single mountain peak changes. The OrganicMaps OSM data can be post-processed with algorithms before visualizing it because it is not updated every minute.

Describe the ideal solution

Run the prominence / topographic isolation algorithm on the mountain peak data. This produces a number for each peak, how prominent it is in the direct area.

The map can display peaks of a certain prominence depending on the zoom level.

Related documentation and implementations:

Describe alternatives you have considered

Other maps also use this solution, if the resources are available to recalculate the peak prominence when the data changes. For example OpenTopoMap.

Additional context

If this feature is not worth the processing or complexity, feel free to close this issue.

**Is your feature request related to a problem? Please describe.** Currently, mountain peaks are shown from the first zoom level where downloaded country details are shown. Every mountain peak is shown on the map, irrespective of its elevation. (see screenshot) Having fewer but more important mountain peaks on the map ensures the map is less cluttered, and more targeted. Especially together with contour lines, this creates a nice overview visualization of a region for the lower zoom levels. The main OSM carto visualization has the same problem, see https://github.com/gravitystorm/openstreetmap-carto/issues/3722. However, that data has to be updatable dynamically without reprocessing the entire world when a single mountain peak changes. The OrganicMaps OSM data can be post-processed with algorithms before visualizing it because it is not updated every minute. **Describe the ideal solution** Run the prominence / topographic isolation algorithm on the mountain peak data. This produces a number for each peak, how prominent it is in the direct area. The map can display peaks of a certain prominence depending on the zoom level. Related documentation and implementations: - https://osm2pgsql.org/doc/manual.html#strategy-discrete-isolation - https://github.com/MathiasGroebe/discrete_isolation - https://wiki.openstreetmap.org/wiki/User:Maxbe/Dominanz_von_Gipfeln (in German) - C implementation https://github.com/der-stefan/OpenTopoMap/blob/e4467cfc2064afc379b0f8e8360db1740099cca3/mapnik/tools/isolation.c **Describe alternatives you have considered** Other maps also use this solution, if the resources are available to recalculate the peak prominence when the data changes. For example OpenTopoMap. **Additional context** If this feature is not worth the processing or complexity, feel free to close this issue. ![image](https://github.com/user-attachments/assets/03c41fd0-8421-4eff-adb2-f35e325fc50a)

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