One thing I get asked a lot when talking to customers, is whether we have our own WMS/WMTS service for supplying vertical imagery. Well the answer to that question is a very easy ‘yes’.
Our BlomURBEX geoserver provides a very easy to use WMS and WMTS service that customers can take advantage of with minimal effort. So the purpose of this blog post is to highlight how easy it is to get started and reasons why using a WMS or WMTS service over traditional, offline imagery files is the way to go.
What is a WMS/WMTS?
A WMS server (Web Map Service) is essentially a protocol for delivering georeferenced imagery via the internet from a large database. In WMS this is normally one image created on the server, then delivered to the user to display imagery for the required area, in this case inside a GIS program.
A WMTS server is basically the same as a WMS server, but where WMS retrieves one image per request, a WMTS server will return a set of predefined tiles in order to display the required imagery. It can also be cached on the client side, reducing the need for frequent requests on the server , so ultimately is faster for the user. The downside of WMTS is that not all GIS software packages fully support it yet.
If you’re a frequent user of aerial imagery, then you should hopefully be familiar with handling digital aerial imagery. This is usually in formats such as Jpg, Tiff, ECW, TAB, MrSID, the list goes on – all of which require storing somewhere and accessing it locally. Using WMS & WMTS removes the whole bulky storage part of the equation, and requires nothing more than a URL and an active internet connection to retrieve the data.
Setting up the WMS/WMTS connection
Now we know what they are, lets get started; to begin with you will need either your user token, or your login credentials to access the imagery with. These will have been supplied to you via your Blom Account Manager. Your user token will be in the form of a long string of text, unique to you, or a simple user name and password.
In this example we’ll connect to our WMS service using QGIS 2.0.1 – a firm favourite open-source GIS package, but our WMS & WMTS servers can be accessed by any other GIS software capable of reading them.
N.b. – our WMS service is fully supported by OGC standards 1.1.1. & 1.3.0 and our WMTS version 1.0.0.
Here we’ve got a some simple building polygons in Bristol and we want to overlay them onto our BlomORTHO imagery;
Lets pull in the imagery; so start by going to ‘Add WMS/WMTS’ server from the toolbar or ‘Add WMS/WMTS layer’ from the Layer menu;
Then hit ‘New’ to bring up a settings box to configure the connection. Now, there are two ways to access our WMS server, as explained above. If you have a user token, which you might have previously used with our API, then you will need to use this as part of the URL;
Just drop your username and password into the appropriate boxes and use the following URL to connect.
When done, press ‘OK’, then select ‘Connect’, and provided you have all the details entered correctly, you should see a list of all available layers to you (above). There are five available;
If you require traditional vertical imagery, select Ortho. Our WMS/WMTS servers also provides access to oblique mosaics, which are oblique images stitched together to give one continuous view facing that orientation.
For this example, we’re going to select Ortho. When you have highlighted Ortho, you need to specify which projection you require. As our example uses OSGB 1936 (EPSG Code 27700) shape files and we want to continue to work in that projection, we’re going to choose that from the list;
Hit ‘OK’ and then ‘Add’; you should now see the imagery as a base layer inside the QGIS workspace window;
That’s it! So now when you zoom, pan and change view, the imagery will refresh and if required, will retrieve more data from the server.
The above process is very similar to repeat in ArcGIS, as well as Global Mapper and MapInfo.
Connecting to the WMTS server is almost identical, but instead you need to use this URL instead;
Then just repeat all the same steps for your user token or username and password.
If you’d like to find out availability and pricing for our WMS/WMTS services, please contact your local Blom office via our website.