consulting and development

maps, GIS and geospatial software

Underwater Map for Diving


The base map’s WM(T)S layer is great, but as it is a raster format, it contains only pixels, not objects that can be filtered and layered in varying order. As a result, the bridges were not rendered over the water but under it.

It is also possible to download vector maps of the region here: However, creating cartography for a new base map from scratch would be a huge and very time-consuming task. Instead, I filtered out the bridges and rendered them on top of the water – but in a way that allows the user to still see the bathymetry below the bridge, see image.


The client and I wanted to change the water colour to match the isarithmic map better. I picked a water polygon from the downloaded data and coloured it darker, see image.


I was now ready to tune the map layout and deliver it to the client. Like other GIS applications, QGIS has a layout designer – here called print composer – which lets you design a static map for e.g. print with legend, scale bar etc, see screenshots below. The final result was exported in PNG format to fit A2 paper in 600dpi resolution resulting in 14031 by 9921 pixels.