And this is how they can be downloaded for a specific area:

> wget http://open.mapquestapi.com/xapi/api/0.6/node[highway=mini_roundabout][bbox=15.86,47.95,16.88,48.70]
> wget http://open.mapquestapi.com/xapi/api/0.6/way[junction=roundabout][bbox=15.86,47.95,16.88,48.70]

Note: Not all XAPI servers are available all of the time. Check this site if the server is down: OSM Wiki – Xapi.

The plugin dialog is quite self-explanatory. You can chose the elevation file, output path and any of the numerous raster formats. The z factor is a bit more mysterious. We will have a look at that in a second. The rest of the dialog is the relief color editor. Pressing Create automatically will give you a color gradient to start with.

Relief tool dialog

But what’s the z factor good for?

I’ve tried a few different settings using free NASA SRTM data and it seems that higher values lead to a smoother relief (Please ignore the water areas):

Update:

As Marco noted in the comments: The z factor is used if the x/y units are different from the z unit.

• If everything is in meters, use z factor 1.0 (default).
• If x/y is in degree and z in meters, use z factor 111120.
• If x/y degree and z is feet, use z factor 370400.

In the example above SRTM rasters are in WGS84 with heights in meters. That’s why the result using a z factor of 100000 looks so good.

In my opinion the results look great even with the coarse SRTM dataset I used. Looking forward to all the great QGIS maps we will see in the future.

substr(osm_name, 0, (clazz = 11 or clazz = 13 or clazz = 15 or clazz = 21)*-1)

to

CASE WHEN (clazz = 11 or clazz = 13 or clazz = 15 or clazz = 21) THEN osm_name END

which is much easier to read and remember.

To avoid roads from being labeled with only their road numbers, I added an additional check that the “osm_name” is longer than six characters. Thanks to Nathan’s syntax highlighting this new and powerful expression based labeling is also comfortable to use.

Conditional labels for an osm2po layer

default labeling

How can we label only the more important roads? Here is an example using OSM data imported into PostGIS using osm2po:

If you have loaded OSM using osm2po, your OSM table will contain a “clazz” attribute. (Check osm2po.config for the exact mapping.) To label only motorways, trunks, primary and secondary roads and nothing else, I wrote this labeling expression:

substr(osm_name, 0, (clazz = 11 or clazz = 13 or clazz = 15 or clazz = 21)*-1)

If clazz equals 11, 13, 15 or 21, the expression returns the value of osm_name. Otherwise it returns an empty string. (All checks will return false or 0 which causes the function to evaluate to substr(osm_name,0,0).) Kudos to Giuseppe Sucameli who explained this on the mailing list.

expression based "conditional" labels

Considering the coarse resolution of geocoded IP addresses, I’ve decided to count the number of unique IP addresses within each area (5×5 degrees). We can make out a lot of activity in Europe, Japan, Brazil and the US. The high number of accesses from the US mid west are due to IPs being mapped to country-level only.

I would love to hear your feedback on this one!

If you want to try it, you can install version 0.4 from the new QGIS Plugin Repository. I’ve also uploaded some test data such as the twitter file used for the animation I presented recently.

I used my Python 2.6 stand-alone installation (not the one in OSGeo4W).

1. Get the Sphinx egg from http://pypi.python.org/pypi/Sphinx
2. If you don’t have it, install setuptools to get the easy_install script http://pypi.python.org/pypi/setuptools
3. In C:\Python26\Scripts run easy_install -U sphinx
4. Get the PyQGIS source from https://github.com/qgis/QGIS-Developer-Cookbook
5. Create a build folder inside the QGIS-Developer-Cookbook
6. Now you can build the Cookbook: sphinx-build "C:\Users\Anita\QGIS\QGIS-Developer-Cookbook\source" "C:\Users\Anita\QGIS\QGIS-Developer-Cookbook\build"

The build folder should now contain the Cookbook .html files.

You can already find symbols/styles described in these posts:

• Colorbrewer color ramp symbols
• “Google Maps” road symbols
• “Google Maps” style for OSM roads

In a previous post, I did already show how to prepare a view that will help get similar looking road labels. And now, here are the necessary symbols: osm_symbols.xml (Load using “Style Manager”.)

Now, you should have all necessary symbols available to create the style. I used the following rules to get the map shown above:

rules for "Google Maps" style

You can download the style here: v_osm_roads_style.qml

Merry Christmas!

OSM styled like "Google Maps"

PS: For water and natural areas, I used Cloudmade’s natural.shp

C:\Users\Anita\temp\osm2po-4.2.30>java -jar osm2po-core-4.2.30-signed.jar prefix=at "C:\Users\Anita\Geodaten\OpenStreetMap Data\austria.osm.pbf"

you should find a folder with the name of the prefix you chose inside the osm2po folder. It contains a log file which in turn provides a command line template for importing the OSM network into PostGIS, e.g.

INFO commandline template: psql -U [username] -d [dbname] -q -f "C:\Users\Anita\temp\osm2po-4.2.30\at\at_2po_4pgr.sql"

Using this template, we can easily import the .sql file into an exiting database. My pgRouting-enabled database is called wien_ogd.

C:\Users\Anita\temp\osm2po-4.2.30\at>psql -U [username] -d wien_ogd -q -f C:\Users\Anita\temp\osm2po-4.2.30\at\at_2po_4pgr.sql

Now, the data is ready for usage in QGIS:

The osm2po table in QGIS

Using “pgRouting Layer” plugin, it’s now straightforward to calculate shortest paths. I had to apply some changes to the plugin code, so please get the latest version from Github.

A shortest path in osm2po network

Using osm2po turned out to be far less painful than I expected and I hope you’ll find this post useful too.