wms

Stamen Watercolor Map Tiles

Adding Basemaps to QGIS With Web Mapping Services

For this final post of 2020, I was looking back through recent projects for something interesting yet brief; I’ve been writing some encyclopedia-length posts lately and wanted to keep this one on the lighter side. In that vein, I’ve decided to share a short list of free web mapping services that I use as basemaps in QGIS (they’ll work in ArcGIS too). This has been on my mind as I’ve recently stumbled upon the OpenTopoMap, which is an alternate stylized version of the OpenStreetMap that looks pretty sharp.

See this earlier post for details, but in short, to connect to these services in QGIS:

QGIS Browser Panel
  1. Select the appropriate web map service type in the browser panel (usually WMS / WMTS or XYZ Tiles), right click, and add new connection.
  2. Give it a meaningful name, paste the appropriate URL into the URL box, click OK.
  3. In the browser panel drill down to see the service, and for WMS / WMTS layers you can drill down further to see specific layers you can add.
  4. Select the layer and drag it into the window, or select, right click, and add the layer to the project.
  5. If the resolution looks off, right click on a blank area of the toolbar and check the Tile Scale Panel. Use this to adjust the zoom for the web map. If the scale bar is greyed out you’ll need to set the map window to the same CRS as the map service: select the layer in the panel, right click, and choose set CRS – set project CRS from layer.
  6. Some web layers may render slowly if you’re zoomed out to the full extent, or even not at all if they contain many features or are super detailed. Conversely, some layers may not render if you’re zoomed too far in, as tiles may not be available at that resolution. Experiment!

If you’re an ArcGIS user see these concise instructions for adding various tile layers. This isn’t something that I’ve ever done, as ArcGIS already has a number of accessible basemaps that you can add.

In the list below, links for the service name take you to either the website version of the service, or to a list of additional layers that you can connect to. The URLs that follow are the actual connections to the service that you’ll use within your GIS package. If you use OSM, OTP, or Stamen in your maps, make sure to cite them (they use Creative Commons Licenses – follow links to their websites for details). The government sources are public domain, but you should still cite them anyway. Happy mapping, and happy holidays!

OpenStreetMap XYZ Tile (global)

http://tile.openstreetmap.org/{z}/{x}/{y}.png

OpenTopoMap XYZ Tile (global)

https://tile.opentopomap.org/{z}/{x}/{y}.png

Stamen XYZ Tile (global) see their website for examples; the image topping this post is from watercolor

http://tile.stamen.com/terrain/{z}/{x}/{y}.png
http://tile.stamen.com/toner/{z}/{x}/{y}.png
http://tile.stamen.com/watercolor/{z}/{x}/{y}.jpg

USGS National Map WMTS (global, but fine detail is US only)

Imagery:
https://basemap.nationalmap.gov/arcgis/rest/services/USGSImageryOnly/MapServer/WMTS/1.0.0/WMTSCapabilities.xml

Imagery & Topo:
https://basemap.nationalmap.gov/arcgis/rest/services/USGSImageryTopo/MapServer/WMTS/1.0.0/WMTSCapabilities.xml

Shaded Relief: 
https://basemap.nationalmap.gov/arcgis/rest/services/USGSShadedReliefOnly/MapServer/WMTS/1.0.0/WMTSCapabilities.xml

Topographic:
https://basemap.nationalmap.gov/arcgis/rest/services/USGSTopo/MapServer/WMTS/1.0.0/WMTSCapabilities.xml

US Census Bureau TIGERweb WMS (US only) see their website for older vintages

Current TIGER features:
https://tigerweb.geo.census.gov/arcgis/services/TIGERweb/tigerWMS_Current/MapServer/WMSServer 

Current physical features:
https://tigerweb.geo.census.gov/arcgis/services/TIGERweb/tigerWMS_PhysicalFeatures/MapServer/WMSServer

Sedona Hike

XYZ Tiles and WMS Layers in QGIS 3

I did a lot of hiking around Sedona, Arizona a few weeks ago, and wanted to map my GPS way points and tracks in QGIS over some WMS (web mapping service) base map layers. I recently switched to QGIS 3 since I need to use that in my book (by the time it comes out 2.18 will be old news), and had to spend time starting from scratch since the plugin I always used was no longer available (ahhh the pitfalls of relying on 3rd party plugins – see my last post on SQLite). I thought I’d share what I learned here.

I was using the OpenLayers plugin in QGIS 2.x as an easy resource to add base maps to my projects. You could pull in layers from OSM, Google, Bing, and others. It turns out that plugin is no longer available for QGIS 3.x. So I searched around and found some suggestions for a different plugin called QuickMapServices which was a great replacement. But alas, that worked in QGIS 3.0 but is not compatible (as of now) for QGIS 3.2.

So I’m back to adding WMS layers manually. There is a new feature in QGIS for adding XYZ Tiles; this is a little better than WMS because the base map can be rendered a bit quicker. I found a tip in the Stack Exchange that you can add an OSM tiles layer with this url:

http://tile.openstreetmap.org/{z}/{x}/{y}.png 

Select XYZ Tiles in the Browser, right click, New connection, give it a name, add the URL. You can modify the X Y Z coordinates where the map centers and zooms by default. Once you’ve created the connection, you can simply drag the OSM layer into the map window to render it.

Adding the OSM XYZ Tiles in QGIS

One problem that always creeps up: when you add other layers and adjust the zoom, sometimes the rendering of the base map looks poor, i.e. the features and labels look blurry or blocky. When you’re pulling data from a web map layer, as you zoom in it swaps out the tiles for more detailed ones appropriate for that scale. But when you’re zooming in QGIS things can get out of synch, as your map window zoom may not be enough to trigger the switch in the map tiles, or those map tiles are just not meant to be rendered at that scale. If you right click on a blank area of the toolbar, you can activate the Tile Scale panel and can use the slider to adjust the window zoom in synch with the tiles, so you can operate at the scales that are appropriate for the tiles. The way points and track for our hike alongside Schnebly Hill Road are shown below, and the labels for the points represent our elevation in feet.

OSM Tile Layer with Tile Scale Panel

If the slider is grayed out, select the OSM layer in the Layers menu, right click, and select Set CRS  – Set Project CRS From Layer. Web mapping services typically use EPSG 3857 Pseudo Mercator as the coordinate reference system / map projection by default. If your other vectors layers aren’t in that system, you can have the base map draw to their system or vice versa by selecting the layer, right clicking, and choosing Set CRS. But for the tile scale to work properly EPSG 3857 must be the project CRS.

Lastly, I’ve always liked the USGS WMS layers, which are never included in the plugins that I’ve seen. The USGS provides layers for: imagery, imagery with topographic features, shaded relief, and the USGS topographic map layer:

https://basemap.nationalmap.gov/arcgis/rest/services

USGS Link for WMS Layer for Topographic Maps

You can click on one of the services, and at the top (in small print) are urls for their services in WMS and WMTS. The last one is a web mapping tile service, which is a bit faster than WMS. Click on the WMTS link, and copy the url from the address in the browser. Then in QGIS select WMS / WMTS layers, right click, add a new connection, give it a name and paste the url. This is url for the topographic map:

https://basemap.nationalmap.gov/arcgis/rest/services/USGSTopo/MapServer/WMTS/1.0.0/WMTSCapabilities.xml

Once again, you can drag the layer into the map window to render it, and you can use the Tile Scale panel to adjust the zoom. Here’s our hike with the topo map as the base:

USGS Topographic Map in QGIS