Tag Archives: OpenLayers

In Publishing interactive web maps using QGIS, I presented two plugins for exporting web maps from QGIS. Today, I want to add an new member to this family: the qgis2web plugin is the successor of qgis-ol3 and combines exports to both OpenLayers3 as well as Leaflet.

The plugin is under active development and currently not all features are supported for both OpenLayers3 and Leaflet, but it’s a very convenient way to kick-off a quick webmapping project.

Here’s an example of an OpenLayers3 preview with enabled popups:

OpenLayers3 preview

OpenLayers3 preview

And here is the same map in Leaflet with the added bonus of a nice address search bar which can be added automatically as well:

Leaflet preview

Leaflet preview

The workflow is really straight forward: select the desired layers and popup settings, pick some appearance extras, and then don’t forget to hit the Update preview button otherwise you might be wondering why nothing happens ;)

I’ll continue testing these plugins and am looking forward to seeing what features the future will bring.


Update 2016-07-31

For the latest installation instructions, please see the official QGIS Server documentation.

This post summarizes my notes about installing QGIS Server on Ubuntu, adding a QGIS project file to the server and using the WMS in an OpenLayers application.


First, it’s useful to figure out the Ubuntu version:

lsb_release -a

Since my server runs “lucid”, I add the following package sources to /etc/apt/sources.list (as described in the QGIS installation documentation)

deb lucid main
deb-src lucid main

Before we can install anything, we need to add the key and update the package list

gpg --keyserver --recv 1F9ADD375CA44993
gpg --export --armor 1F9ADD375CA44993 | sudo apt-key add -
sudo apt-get update

Now we can install QGIS Server and the necessary Apache package

sudo apt-get install qgis-mapserver libapache2-mod-fcgid

It never hurts to restart Apache :)

sudo /etc/init.d/apache2 restart

Let’s test the installation before we proceed. The GetCapabilities request should already work

Adding a QGIS project file

It’s time to add a QGIS project to our server. To do that, we move to the QGIS Server folder

cd /usr/lib/cgi-bin

where you should find qgis_mapserv.fcgi and wms_metadata.xml.
I’ve decided to have one folder for each project file. My first project is “vienna”.

sudo mkdir vienna
cd vienna

qgis_mapserv.fcgi and wms_metadata.xml can now be linked into this new folder

sudo ln -s ../qgis_mapserv.fcgi .
sudo ln -s ../wms_metadata.xml .

The only thing that’s missing anymore is a QGIS project file. It can be copied or linked into the folder. After restarting Apache, we should be good to go.

Let’s test the setup using “Add WMS Layer” in QGIS by adding the service URL such as

and ticking “Ignore GetMap URI …” and “Ignore GetFeature URI …”.

After clicking “Connect”, all layers from the project file we added should get listed and we can select and load them.

QGIS Server can serve as many project files as you want. There are different ways to organize your server but I would simply add a new folder (like the “vienna” folder in this example) and link in the executable and project file.

Using QGIS Server WMS in OpenLayers

Of course QGIS Server doesn’t just talk to QGIS Desktop but to any other WMS client that conforms to the standard. One classic use case is to add the WMS layers to an OpenLayers application. This is rather simple but I’ll add it here for the sake of completeness:

I used to have a Geoserver WMS base layer in my application. The only lines of code that needed to be changed to migrate to QGIS Server were the service URL and the layer names.

wms = new OpenLayers.Layer.WMS(
    'roads', "",
        layers: 'roads',
        format: 'image/png';
        bgcolor: '#fafafa'
        buffer: 1,
        isBaseLayer: true,
        graphicZIndex: 0,

Standardized services are great!

Recently, @simo has posted an elegant solution for defining custom styles for Google Maps layers in OpenLayers on gis.stackexchange. An example with source can be found at The idea seems to be to use a StyledMapType:

The StyledMapType allows you to customize the presentation of the standard Google base maps, changing the visual display of such elements as roads, parks, and built-up areas to reflect a different style than that used in the default map type.

How great would it be if it was possible to define such styles in QGIS OpenLayers plugin too!

Heat up your maps!

The project is called “OLHeatmap” and the results look promising:

an "inverted heatmap"

Try it out yourself using the Live Demo.

You find the project’s homepage at Sourceforge.

There is a new layer class in OpenLayers API: OpenLayers.Layer.WMS.Post [1]. – Great work!

While the “normal” OpenLayers.Layer.WMS class requests maps via HTTP GET, this new class sends the request via HTTP POST. This way, we can now send big client-side created SLD files in our GetMap requests that used to exceed size limits of GET.

This code snippet shows the basic use of OpenLayers.Layer.WMS.Post with a client-side created SLD. You’ll need at least OpenLayers 2.9 to test this on your server. (A full example can be found at

var sld = 'define your SLD here';

wms = new OpenLayers.Layer.WMS.Post(
    'layers': 'myNs:layername',
    format: 'image/jpeg',
    sld_body: sld
    unsupportedBrowsers: []

Setting unsupportedBrowsers to an empty list is important! This list by default contains [“mozilla”, “firefox”, “opera”]. These browsers support long GET requests so the developers argued that these browsers wouldn’t need to use POST. Well, turns out that they do ;)

I performed a small stress test using an SLD with approximately 1,000 rules being applied on a big city road network. While my browser would willingly send a GET request of that size, Apache doesn’t want to accept it. So, I tried the POST way and it turns out that it really works! (But it’s slow, very slow …)

Thanks to the developers for yet another great feature!


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