Some thoughts about data formats.

README.md

@@ -12,4 +12,30 @@ The viewport on the underlying map
 
 The map itself (and its overlays)
 
+## Data formats
+
+There is a number of data formats more or less specific to geography and hiking, such as:
+
+* [GPX 1.1 Schema Documentation](https://www.topografix.com/GPX/1/1/)
+* [GeoJSON](https://geojson.org/)
+* [Keyhole Markup Language - Wikipedia](https://en.m.wikipedia.org/wiki/Keyhole_Markup_Language)
+* [Elements — OpenStreetMap Wiki](https://wiki.openstreetmap.org/wiki/Elements)
+* [<svg> - SVG: Scalable Vector Graphics | MDN](https://developer.mozilla.org/en-US/docs/Web/SVG/Element/svg)
+
+SVG is very generic and is used to draw 2D figures in HTML applications and doesn't care about geography.
+
+KML, GeoJSON and OSM elements have been designed to represent generic geographical points and shapes. 
+
+GPX is more specific, having been designed to represent routes and tracks and its semantices are directly useable in our application.
+
+The strucure of our components and indexes can therefore follow the GPX format.
+
+OSM elements is interesting to extract information from the OSM DB, either by querying their API or by downloading portions of the database.
+
+GeoJSON might be of interest as an intermediate format since a number of JS libraries have been developped to perform queries or draw GeoJSON data as SVG.
+
+KML might be considered as an import format.
+
+And SVG, of course will be used to render tracks and routes on a map since its elements are directly supported by React.
+