Ukrainian indie developer Igor Vasylenko presented the application "Mandra" - a free offline map of the Carpathians for hiking. It offers over a hundred routes with detailed elevations, as well as markings of 727 water sources and 615 parking lots.
Ukrainian indie developer Igor Vasylenko presented the application "Mandra" - a free offline map of the Carpathians for hiking. It offers over a hundred routes with detailed elevations, as well as markings of 727 water sources and 615 parking lots.
The developer told dev.ua about this.
The main feature of the application is the ability to work completely without a mobile network. To do this, the user only needs to download an offline package of about 126 MB in size once.
From a technical point of view, "Mandra" is built on the Flutter framework, and MapLibre Native is responsible for working with the map. The offline map combines vector tiles in the PMTiles format and raster relief. To read data directly from the archive in the smartphone's memory, the application raises the local HTTP server to loopback. Depending on the coverage area, the engine decides where to get the tiles - from the local disk or the network.
In addition, the application allows you to import your own GPX tracks and calculates distance and elevation gain based on its own detailed terrain model. For each route, peak or settlement, separate pages with an interactive map have been created on the mandra.in.ua website, which is generated from a single data catalog.
During development, Vasylenko faced several technical challenges:
Due to the lack of an R-tree module in the built-in SQLite on Android, spatial object search had to be implemented through regular indexes.
The offline package download was interrupted by mobile operators after 50 MiB, so the developer implemented a mechanism for downloading from HTTP Range and automatic connection reconnection.
Interacting with the Google Play rating dialog required analyzing the application's lifecycle, as it does not return direct errors on failure.
Currently, "Mandra" has already crossed the mark of over a thousand downloads on Google Play and has an average rating of 5.0. The application is completely free, contains no advertising, paid subscriptions, and does not require registration. It is developed and supported at the author's own expense as a private indie project for the community of Ukrainian tourists.
