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> All components developed by Qwant Maps are open source so that users can contribute directly to improve their experience with the map: they can contribute eit

> All components developed by Qwant Maps are open source so that users can contribute directly to improve their experience with the map: they can contribute either to the Qwant Maps code or to the enrichment of the data directly in OpenStreetMap. This is an important takeaway. One of the pain points in the OpenStreetMap experience has been lack of performance of the reverse geocoding engine (input lat/lon, get POIs/adress). Or so I hear/see. It looks like they worked around this by only letting the user click on known POIs. One small nitpick: I find the simplified polygons to be... too polygonal (forests, bodies of water, etc) at lower zoom levels. I don't know much about this field, but that's probably a result of not picking the right points when reducing the shape complexity? A bit like what bilinear/other filtering does for raster.

rathel 7y ago
The simplified polygons are a result of using vector tiles, more specifically from OpenMapTiles project, as noted in copyright notice. They need to be simplified in order to achieve reasonable size. Although we can argue how much is too much.
- MayeulC 7y ago
  This is true, but you can be smarter about which points you prune from the polygon. If you take a random polygon and delete random points, you will likely end up with a pointy shape (more so if you only leave a triangle). I don't see why vector tiles should lower the end result's quality. In the end this is strictly an aliasing issue. Take those two zoom levels as an example. In the middle of the screen, a big portion of the forest is discarded: https://www.qwant.com/maps/#map=7.92/50.4850901/16.1876218 https://www.qwant.com/maps/#map=7.92/50.4850901/16.1876218 https://www.qwant.com/maps/#map=8.10/50.4787168/16.2208950 https://www.qwant.com/maps/#map=8.10/50.4787168/16.2208950 This isn't a very good example because those polygons were likely distinct, but a better job could be done by joining them. I wonder what kind of data is available to the vector engine. Would the pruning/simplification be done server-side, or client-side (with the client only requesting parts of the dataset)? In the later case, I feel like a smarter ordering of the primitives, and maybe some hinting metadata, could make a visible difference already. On the other hand, it seems that they went with splines instead of polygons for roads, which produces a smoothed-out result. I think they should probably do the same for water bodies and green areas at lower zoom levels.

rathel 7y ago

The simplified polygons are a result of using vector tiles, more specifically from OpenMapTiles project, as noted in copyright notice. They need to be simplified in order to achieve reasonable size. Although we can argue how much is too much.

MayeulC 7y ago
This is true, but you can be smarter about which points you prune from the polygon. If you take a random polygon and delete random points, you will likely end up with a pointy shape (more so if you only leave a triangle). I don't see why vector tiles should lower the end result's quality. In the end this is strictly an aliasing issue. Take those two zoom levels as an example. In the middle of the screen, a big portion of the forest is discarded: https://www.qwant.com/maps/#map=7.92/50.4850901/16.1876218 https://www.qwant.com/maps/#map=7.92/50.4850901/16.1876218 https://www.qwant.com/maps/#map=8.10/50.4787168/16.2208950 https://www.qwant.com/maps/#map=8.10/50.4787168/16.2208950 This isn't a very good example because those polygons were likely distinct, but a better job could be done by joining them. I wonder what kind of data is available to the vector engine. Would the pruning/simplification be done server-side, or client-side (with the client only requesting parts of the dataset)? In the later case, I feel like a smarter ordering of the primitives, and maybe some hinting metadata, could make a visible difference already. On the other hand, it seems that they went with splines instead of polygons for roads, which produces a smoothed-out result. I think they should probably do the same for water bodies and green areas at lower zoom levels.