OpenStreetMap Switzerland LV95

Using maps in a local coordinate system has a great advantage in using them with your data in the same coordinate system. You do not have to post-process the data with transformation which can lead to less precise visualization and placement of your data. The drawback is a little bit harder to set up an OpenLayers library, but then the result is perfect!

Swiss OSM LV95

Using a different coordinate system such as WGS84 (EPSG::4326), Switzerland CH1903+ / LV95 (EPSG::2056), Czechia (EPSG::5514) or France Lambert-93 (EPSG::2154) have great advantages when they are used with external data sources in the same coordinate system.

Switzerland and Czech Republic using Bessel 1841 (EPSG::7004) and France using GRS80 ellipsoid (EPSG::7019). For Switzerland’s projected coordinate system (in meters) it means, that there has to be a transformation to WGS84 ellipsoid (in PROJ4 - tag TOWGS84 with parameters).

Instead of WGS84 tiles is not possible to project the whole world, because distortions of area out of the bounding box of the coordinate system are extreme. But if you want to use local data in CH1903+ it is the best choice. The transformation between Bessel 1841 and WGS84 ellipsoid is within a 1-meter precision, but even this 1-meter precision could be deformed and move your data.

Adjust style for CH1903+

The steps for creating your own style are almost the same as for tiles in WGS84.

1. Create a style in Spherical Mercator in MapTiler Customize or MapTiler Editor

2. Download the style

3. Edit name and URL for tiles - e.g. from "url": "https://api.maptiler.com/tiles/v3/tiles.json?key={key}" to "url": "https://api.maptiler.com/tiles/v3-2056/tiles.json?key={key}"

The next step is special for CH1903+

4. There has to be adjusted the minzoom value to reflect the situation that Switzerland has zooms from 0 to 8 instead of Spherical Mercator or WGS84 which have zooms from 0 to 14.

5. Then upload back into MapTiler Cloud

Conclusion

Using tiles in CH1903+ is very useful in cooperation with your data in this coordinate system. A little bit harder setup of OpenLayers library for showing vector tiles is a small drawback, BUT when you need a perfect overlay with your data it is the right approach.

Useful links

OpenStreetMap in WGS84
Swiss Government Data