Fossgis: mobile maps with an offline leaflet client - Arne Schubert¶

Tags: fossgis, geo

(One of my summaries of a talk at the 2017 fossgis conference).

The offline client is called “Mops”, it is a demo project for the german railways.

Some problems with the normally used paper maps:

• They’re quickly not up-to-date anymore.

• The big size is a problem when walking around outside.

• The information density is low.

Regarding apps: there are no generic solutions for offline map apps.

What they tried was an individual custom solution. Some of the features:

• GPS.

• Dynamic selection via the current location.

• Offline support.

• Search!

• Usability/look-and-feel should be good.

To build the app, you need to select the area you want to use from your database, select extra layers, you need to style it and then the app needs to be deployed.

They made a hybrid app. As much as possible was done with OS-independend software such as “leaflet” (a javascript map library like openlayers). This limits the amount of specific work you need to do for IOS/android.

Technically, they used GeoPackage as the exchange/container format.

• You can use it offline.

• Spatial queries are possible.

• Raster data is pre-rendered as tiles. (“mbtiles”)

• And… it has very good compatibility.

There are still more possibilities. Reading QR codes. Using the compass. Using other sensors. Entering/adjusting data.

A note on leaflet: it works better on mobile phones than openlayers does. Especially when rendering features.