The 10 best free-to-use map layers
Whenever you are visualizing GIS data you are likely to use some base layer as a background. Nine out of ten times you would probably be using open street map, but there are multiple cases in which other base layers might be of value! In this short article I would like to take you through some interesting and (most importantly) free base layers that are out there.
The layers I mention below are by no means an exhaustive list. There is a large (and every day increasing) number of public base layers out there, more then I could ever hope to list. Especially when you would include national public data sets published by respective governments the possibilities are endless. (In this article I only list globally available ones)
Though this article is not meant as a complete list of base layers, it is meant to encourage people to look beyond the standard build-in datasets they are familiar with and see what else might be out there. In my opinion there are many interesting free and easy to use map layers that are rather under-used.
A small note on adding base layers
Base layers are usually available in one of the following protocols: WMTS, WMS, XYZ, WFS, vector tiles or WCS. A dataset that is made available in such a protocol has it’s own unique url. Almost all viewers and JS libraries allow you to add your own preferred base layer(s) by supplying this particular url.
In QGIS (desktop) for example you can add a connection in the browser pane
If you are looking for an online viewer you can add these protocols in your Ellipsis Drive via the browse pane as well.
Topographic map
This layer from open topo is somewhat similar to open street map but it is more focussed on terrain types and features contour lines giving this layer more of a ‘hiking map’ look and feel.
The open topo map can be used via the XYZ protocol it’s url being:
https://a.tile.opentopomap.org/{z}/{x}/{y}.png
3D buildings
This is one of my personal favorites. I use it a lot when I want to display some city related data with a bit of a ‘wow factor’. With open street map 3D buildings you get a layer with geometric outlines of buildings including their height!
The dataset is available under the XYZ protocol, but only at zoomlevel 15.
https://a.data.osmbuildings.org/0.2/ph2apjye/tile/15/{x}/{y}.json
The world by night
If you are in for a new view of the world, this base layer by Mundialis might be a good option for you! It show the world by night and can be used in cases you want to set a certain mood in your app or if you want to provide a layer that gives a good feel of population densities.
The layer can be used via WMS:
https://ows.mundialis.de/services/service
Global elevation data
Definitely one of the most useful free layers out there. This layer using NASA data contains all global elevation data at a resolution of 30m. You can use it to display altitude or hill shade on a flat map, but personally I mostly use it to apply a 3D elevation lift to my map (using terrainRGB in mapLibre or mapBox) see my article here on how to do this.
The layer is hosted by Ellipsis Drive as both a WMTS and WCS:
Hourly updated fire hotspots from Modis
Staying in the NASA theme there is the highly up to date fire hazard layer. Of course this layer is only interesting when you are dealing with up to date fire risks but this is just one example of the risk maps that NASA is publishing. When you are creating risk maps of any sort I definitely recommend you to checkout the free NASA and also ESA coppernicus maps.
The map is available as wms. You however do need to get a free map token from here:
https://firms.modaps.eosdis.nasa.gov/mapserver/wms-info/
https://firms.modaps.eosdis.nasa.gov/mapserver/wms/fires/{your map key}/fires_landsat_24
Daily air quality map
This free base layer offered by Caeli based on Tropomi data provides a near real time (every 24h) air quality map of the world. This layer can be very interesting whenever you work with atmospheric data or when creating health related dashboards.
This layer is hosted by Ellipsis Drive and available as WMTS and WCS
Natural background layer
A nice open data set that lends it self really well as a background map. The only downside is that the resolution is relatively low. But when it comes to displaying
Precipitation
A free data set containing the monthly temperature averages for each month. There is 12 layers, each layer being one month. This base layer can be a good pick if you need a compare layer to for example current day temperatures or when using other climate related data.
This data set is hosted on Ellipsis Drive and available as both a WMTS and WCS:
The moon!
Alright, alright you are very unlikely to ever really need this map in real life. But just to give you a sense of what is out there… You can actually get base layers from our moon and even mars and some other planets.
Maybe one day when we become a multi-planetary species we can put these layers to work…
Free Copernicus data
Via several Diaz projects Copernicus data is now finally available via a free WMS service on top of the old download options via the Open Access Hub. The data is still a bit raw, but since it is so up to data I think it is very well worth mentioning in this list of highlights.
The Coppernicus data is available as a WMTS with multiple layers.
https://viewer.globalland.vgt.vito.be/mapcache/wmts?service=wmts&request=GetCapabilities
Joining in
These free to use layers are just the tip of the ice berg of open data that is out there and I would like to encourage anyone managing open GIS data to publish it as online maps as well! This really helps with the adaptation of new data and the general advancement of the GIS domain.
Publishing GIS data to the web used to be rather hard task. You needed to create a GeoServer and use that to publish your data. However nowadays this process comes with a lot less friction. With online tools such as mapbox or Ellipsis Drive you can publish your files as online maps instantly, without any infrastructure. You can for example checkout this tutorial to see how to publish GIS data to the web.
I hope that with the recent reduction in friction when it comes to publishing GIS data, more and more people will join in!
