The Map Is Not The Territory

A blog by Christian Willmes.

My summary of the FOSS4G 2016

| categories: conference, open source, geospatial, osgeo, research | View Comments

Last week I attended the FOSS4G 2016 conference in Bonn. I am still digesting my impressions, because there were a lot of them.
First, the location was really great. The new WCCB around the former german Bundestag parliament building is just beautiful, the technical facilities are brand new. I never sat in more comfortable chairs during a conference before. :-) See the FOSS4G flickr group photos to get an impression of the location (also embedded at the end of this post).

Then, the weather was just amazing, all three conference days with temperature of above 30°C, the venue is directly located at the river front, so you could just step outside and enjoy the weather with a beautiful view on the ships going on the Rhine river.

Besides this perfect boundary conditions for a successful conference, the presentations and talks were of very high quality and quantity too. The programm was very well selcted.

But one of the most remarkable thigs about FOSS4G 2016 is, that the video streaming and recordings of every talk of the conference were just perfect. I think this is because the @c3voc from the famous Chaos Computer Club (CCC) was in charge. Which is just priceless, or in other terms I know of no company you can hire to deliver such a video streaming setup, besides (maybe) a professional bradcasting company. You can find all the recordings from here, enjoy!

Additionally, I had two talks which went pretty well I think.

PaleoMaps talk

My first talk was on the first day of the conference, Wednesday 24th August, 15h at the Fireplace Room. The talk was about a new project we started within our Collaborative Research Centre, titled PaleoMaps: SDI for paleoenvironment GIS data".

Semantic MediaWiki @ OSGeo Wiki talk

My second talk was on the second day of the conference, Thursday 25th August, 12h in the Plenary Office. This talk was about my endeavours to improve the OSGeo wiki for collaboratively storing and handling structured information and data. The talk is titled "SMW @ OSGeo Wiki – How semantics improve the wiki and facilitate a collaborative database for OSGeo".

The conference

The rest of the conference was even more awesome. I was really happy to see the rising amount of talks concerning Linked Data and the Semantic Web. Here is a short list of talks I recommend you to watch the recordings:

  • How Linked Open Data finds the bar near you (Rob van Loon): Abstract | Video
  • Integrating the spatial web with linked open data using GeoDCAT-AP (Paul van Genuchten) : Abstract | Video
  • Spatial data and the Search engines (Paul van Genuchten): Abstract | Video
  • Leaflet.annotate - Semantic markup for geographic web maps in HTML (Malte Reißig): Abstract | Video

The talks on GeoNode and on CKAN were also very interesting to me, because I use those applications as Backend and Middleware for the Research Data Infrastrucutre CRC806-Database, that I develop, build and maintain during my research job at University of Cologne.

  • The Evolution of the GeoNode Community (Jeffrey Johnson): Abstract | Video
  • Implementing Open Geospatial Data Portals with CKAN, pycsw and PublicaMundi: the case (Angelos Tzotsos): Abstract | Video
  • A RESTful API for linking geodata (Francesco Bartoli): Abstract | Video

And one talk, I really want to recommend, is the last Keynote given by Peter Küsterer. The talk was titled: "Sahana as an indispensable tool for disaster management", and it told about the application of the Sahana software to manage the refugee situation in late summer of 2015 in Germany, when >1.000.000 refugees made their way to Germany.

And finally there was the closing ceremony and there were some Awards. The most important award, the Sol Katz Award went to Jeff McKenna, who could not attend the conference, but was able to send thanks and acceptance of the award through a great video message. Jonas Eberle got the best presentation award from the the Academic Track, the award for the best Poster went to Lorraine Barrythat was awarded with 500,- €, and Evan Rouault won the best developer award, that is recognized with 1000,- €. And here you can enjoy the many fotos, that were collected in the FOSS4G flickr pool:

And next year Boston!

The organizing team of the upcoming next FOSS4G 2017, was showing a "wicked awesome" video presenting the next hosting location of the conference series. I am really got fixed to the idea of going to Boston next year. Need to come up with a new idea or project, that I can present there to get my travel fundet by my University. :-)

Have fun!


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Preparations for FOSS4G 2016 in Bonn

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FOSS4G Conference

I am very much looking forward to participate in the 2016 FOSS4G conference taking place in Bonn, Germany this year. FOSS4G is one of the conferences I try to participate every year because I really like the spirit of the Open Source Geospatial community that gathers on this international conference series once a year during the dog days. My first FOSS4G was 2010 in Barcelona, then I was in Nottingham 2013 (my blog post about 2013 FOSS4G), 2014 I also attended at FOSS4G in Portland, about which I also blogged. So this year will be my fourth FOSS4G participation! And best is, it will be just around the corner from my home town Cologne, so I can stay at home during the conference and do not need to book travel and a hotel, which is quite weird for participating in an international conference :), but also quite comfortable and indeed cost saving. I will give two talks and will chair one session, on which I introduce some details in the following.

PaleoMaps talk

My first talk will be on the first day of the conference, Wednesday 24th August, 15h at the Fireplace Room. The talk will be about a new project we started within our Collaborative Research Centre, titled PaleoMaps: SDI for paleoenvironment GIS data". Strikingly (to me), the talk has the ID #555 in the conference system :). Here is the abstract of the talk:

Paleoenvironmental studies and according information (data) are abundantly pub-lished and available in the scientific record. However, GIS-based paleoenvironmental information and datasets are comparably rare. Here, we present an OpenScience approach for collecting and creating GIS-based data and maps of paleoenvironments, and publishing them in a web based Spatial Data Infrastructure (SDI),for access by the archaeology and paleoenvironment communities. The Open Science approach to the publication of data, allows to properly cite the published datasets as bibliographic sources in research that builds upon these data sets.This paper has its focus on the implementation and setup of the Free and OpenSource Software for Geospatial (FOSS4G) based SDI, and on the workflow for compiling and publishing the GIS data.

I submitted the talk for the FOSS4G Academic Track, on which I also volunteer as a reviewer and as a Track Editor, about which I will explain further below some more.

Semantic MediaWiki @ OSGeo Wiki talk

My second talk will be on the second day of the conference, Thursday 25th August, 12h in the Plenary Office. This talk is about my endeavours to improve the OSGeo wiki for collaboratively storing and handling structured information and data. The talk is titled "SMW @ OSGeo Wiki – How semantics improve the wiki and facilitate a collaborative database for OSGeo". Coincidentally, the talk has the ID #111, which also bugs me a bit :). The abstract of the talk is given in the following:

Recently, the OSGeo wiki was updated from an ancient version to the current LTS release of MediaWiki. This update broke the functionality of the first OSGeo wiki usermap implementation, dating back to 2008. The map shows the location of OSGeo members on a web map integrated into the wiki. A new version of the usermap [1] was implemented based on Semantic MediaWiki (SMW) [2] to replace the first usermap [3]. This presentation will describe the new features and possibilities that SMW adds to the OSGeo Wiki. After a short introduction to SMW, based on the OSGeo member model, that recently replaced the old usermap, a basic data model and its use in the wiki, as well as major features of SMW are explained. The data model development approach, using mobo [4], applied for implementing the OSGeo Members map will be explained briefly. Additionally, simple examples for bootstrapping smaller semantic models are given too. The presentation concludes with ideas for further applications of SMW in the OSGeo wiki, like the already implemented Advocate and Board lists pages, as well as possible applications, for example a collaboratively maintained OSGeo/FOSS4G service provider directory, or even a collaborative open geospatial data directory are proposed or suggested.

Session Chair

I also volunteer as Session Chair on the third day of the conference, Friday 26th August, Tunnel. The session will host two very interesting talks by well known members of the OSGeo community. The first talk will be given by Pirmin Kalberer on "Using and extending GeoPackages". And the second talk will be given by Sean Gillies on the topic GeoJSON and the IETF.

Academic Track

Additionally, I volunteered for organizing the Academic Track, together with Franz-Josef and Pradeepkumar. I was involved in three paper reviews as a reviewer, and in seven contributions as Track Editor, assigning reviewers and overseeing the review process.


I am sure, this will be a great conference. It will take place at the newly opened World Conference Center Bonn (WCCB), which is build around the former German Bundestag building, including the former Parliaments Plenary Chamber and further facilities of the Bonner Bundestag. It will be a great experience to meet at this historic, and also architecturally interesting place. As said, I am really looking forward to experience this special place, as well to meet all the great people of the Open Source Geospatial community.


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A 32c3 blog post, from someone who was not there

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As it is now almost tradition for me to follow the CCC Congress via video streaming between the years, during major years end home cleanup and holiday chill, I want to take note about some interesting talks and recommend you to see the recordings of this talks, embedded in this post.

First off, the video streaming, recording and its web publication delivered by the CCC Video Operation Center is top notch! It is possible to follow every talk, some of them even simultaneously translated and with sub texts in several languages. The videos were live streamed in several formats, embedded HTML5 video, or video streams to play from video player applications, such as VLC. Later on the video are published on the servers, without ads and without tracking. Good services for embedding and sharing of the videos are provided too. It's really awesome and most important it's rock solid and professional. I am really looking forward to FOSS4G 2016 in Bonn, where these guys will be doing the video recordings for the FOSS4G Conference.


The second part of this talk is very interesting, the presenter of this part was able to in some way reverse engineer, or at least to successfully trace, how the variables are tuned in the Volkswagen engines, for cheating the emissions on the test stands.

A pity that the first guy took so much time, because he did not told anything new. If you read for example the Spiegel Online headlines according to the #dieselgate you know evereything he said. Sadly, the talk was aborted by the moderator in the end, when the talk was getting most interesting, because they ran out of time.

Let's Encrypt

Let's encrypt is a great new service, for anyone running a web server or web site. This service makes it possible to get TLS/SSL certificates, accepted by all the major browsers, for free! I tried it on this very web site and server, and got it installed in about 5 minutes. Really easy and a great service indeed!

Onion Tor Talks

The first talk, State of the Onion, is getting a tradition at CCC Congress. Here the lead persons of the Tor project are delivering the latest news about the project to the community. An absolute must see, for anyone interested in security, privacy and decency on the internet.

The second Tor talk is more technical, but also shows interesting statistics and has some stories about for example, how Facebook uses Tor and Onion sites to deliver its services in repressional regimes, such as Saudi Arabia, Russia or China.

A new kid on the block

Here, Katharina Nocun delivers THE "anti Facebook" Talk of this years Congress. The new kid on the block is in this case the open source decentralized Diaspora* social network. If Diaspora* is really new, is object-able, but she has some very valid observations to share and reminds us of why it is not a good idea to trust in a central commercial entity with to much of your private informations and data. Here is also a good article in German about her and this talk.

One year of securitarian drift in France

A very interesting talk, in the aftermath of the Paris attacks and the Charlie Hebdo attack in France, was given by two French activists form the la quadrature du net, the French CCC (in some sense). The French authorities and politics are strengthen the surveillance and diminishing the freedom of speech, because they think this increases the security. The two activists tell a quite shocking story about the current situation in france.

There were of course a lot more very interesting talks, but I leave it to the many crowds of the inter webs to report on this other talks. You can find all recordings on the CCC media servers, to virtually participate in the Congress like I did.

A happy new year to you all and of course have fun!


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Misleading Chromium and Google Chrome warning message for self signed SSL certificates

| categories: webdev, ubuntu, open source, server | View Comments

Since some time, I am aware of a new Chromium or Google Chrome web browser warnig message concerning not "trusted" SSL certificates for SSL secured websites.

I guess that this new warnig message is part of Google's (basicaly good) campaign to support and promote the use of SSL. Google announced this campaign under the title HTTPS Everywhere at Google I/O 2014. They are talking about things like good citizenship of the web in the context of SSL.

Screenshot of the Chromium "Privacy error" warning, shown on accessing my own server via HTTPS.

The problem with that message is, that colleagues and freinds with whom I want to share data through my server, get scared by this misleading message from Chromium and Chrome, they get back to me saying that there might be somethig not working or wrong with my server. Then I have to try to explain to people, mostly barely knowing the difference between a website and a server, about SSL certificates and HTTPS, and convince them to trust me and not that serious appearing message... This does basically only work for people I know a fair bit. Some people with whom I need to work, but not know, will most probably not trust me and are scared away by this message, if they don't know enough about the matter of SSL encrypted HTTPS. And sorry Google, this is not good.

Even more misleading message chown by Chrome/Chromium if the user proceeds through the "Advanced" option.

In my view this warning message is not just very suggestive, in a way that it compromises the trust in accessing data and web applications on my server through HTTPS, it is also wrong in the content it claims. It says that accessing my server is unsafe. Which is not the case! And anybody who thinks that is the case when using a self signed certificate, please comment to this post and educate me.

I have now issued a free SSL certificate from StartSSL for the HTTPS configuration of my webserver, to get rid of this wrong and annoying warning by Chrome/Chromium. Which I am very uncomfortable with, because I do not trust this company in any way. And why the heck should I or anyone? I do not know anything about the people behind this company. And why the heck should I care? I just want to have a minumum protection for entering passwords and data into my webapplictation by providing HTTPS connection to my server. Since the Snowden revelations it is clear that SSL can be decrypted by knowledgeable enough "agency" anyway.... None the less, I am forced to trust in some company, which sells trust (which is plain wrong on so many different levels of implementation and from so many different angles of view on that matter). And I also need to force my colleagues and friends to trust in this company, from which I got some trust... This trust I gained throgh receiving and confirming an email send to an address on my domain name. That I host my Email not on the server, the domain is registered for, and where I use that certificate, does not matter for that company to trust me... :P.

On a side note, the warnings issued by FireFox or IE are way more polite, and do not scare away people from accessing my server (using a self signed certificate), they just accept the "asumed" and way less severe risk warnigs of those browsers notifications.

Finally, I have a question to you all. Please tell me, how a Self Signed Certificate is in any way less secure, than a "certified" and "trusted" one? The connection itself is not more or less secure, its just the trust. And as said, I am not comfortable with trusting some companies who can grant (sell) trust... This trust must come from the provider of the application and maintainer of the server that is to be accessed, I think.

Have fun and a good start into 2015!


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GeoNode installation on two hard disks

| categories: webdev, ubuntu, open source, geospatial, server | View Comments

I had to install GeoNode on a server with a (small) hard disk for the OS (Ubuntu Server) + software, and a second larger hard disk volume for the data. If you install geonode from the package source via apt-get, like me, you need to adapt the data locations to use the large hard disk volume. Otherwise, the data will end up on the small hard disk, where the GeoNode application is installed by default.

Because I had some work to find the best way on configuring the system in such an environment, I thought it would be good to write it into the internet, so that other people searching for solutions can find some.

System setup

As already mentioned the server runs a Ubuntu Server 14.04 LTS OS. GeoNode is installed via package install:

$ sudo add-apt-repository ppa:geonode/testing
$ sudo apt-get update
$ sudo apt-get install geonode

The second larger hard disk is mounted into '/media/data'. The goal is to have at least the most locations, where geonode stores its data on this volume.


According to an equiry on the geonode-users email list (thanks for helpfull answers to Ariel and Matthew), the following locations store the data, and will grow big over time.


In the following, a solution for each of these locations is given.

GeoNode/GeoServer data directory

$ sudo mkdir /media/data/geoserver
$ cd /media/data/geoserver
$ mkdir data
$ cd /usr/share/geoserver
$ sudo ln -s /media/data/geoserver/data/ data
$ sudo chown tomcat7:tomcat7 data -R

Upload directory

$ cd /var/www/geonode
$ sudo mv uploaded /media/data/geonode/
$ sudo ln -s /media/data/geonode/uploaded/ uploaded
$ sudo chown www-data uploaded -R

Tomcat temp (cache) dir

Tomcat will write the cached tiles of GeoNode's GeoWebCache instance, which can get very big, into the tomcat temporary folder. The path of the temporary directory is defined in an environment variable, which is configured in the tomcat init/startup script.

$ cd /etc/init.d
$ sudo nano tomcat7

Find the line


...change it to


Postgresql tablespace

The hardest part of the configuration is to change the file system locations of the postgresql database and its tables. At first we create a directory for the postgresql storage.

$ vmadmin@geonode:/media/data$ mkdir postgresql
$ sudo chown postgres postgresql/ -R
$ cd postgresql/
$ mkdir data
$ sudo chown postgres data/ -R

Next we set the table spaces:

$ sudo su postgres
$ psql
CREATE TABLESPACE exthd LOCATION '/media/data/postgresql/data';

ALTER DATABASE geonode SET default_tablespace = exthd;

\connect geonode

Alter the tables that grow big to new tablespace:

ALTER TABLE documents_document SET TABLESPACE exthd;
ALTER TABLE layers_attribute SET TABLESPACE exthd;
ALTER TABLE layers_layer SET TABLESPACE exthd;
ALTER TABLE layers_layer_styles SET TABLESPACE exthd;
ALTER TABLE layers_layerfile SET TABLESPACE exthd;
ALTER TABLE layers_style SET TABLESPACE exthd;
ALTER TABLE layers_uploadsession SET TABLESPACE exthd;
ALTER TABLE maps_maplayer SET TABLESPACE exthd;
ALTER TABLE maps_mapsnapshot SET TABLESPACE exthd;
ALTER TABLE services_service SET TABLESPACE exthd;
ALTER TABLE services_servicelayer SET TABLESPACE exthd;
ALTER TABLE services_serviceprofilerole SET TABLESPACE exthd;
ALTER TABLE services_webserviceharvestlayersjob SET TABLESPACE exthd;
ALTER TABLE services_webserviceregistrationjob SET TABLESPACE exthd;
ALTER TABLE upload_upload SET TABLESPACE exthd;
ALTER TABLE upload_uploadfile SET TABLESPACE exthd;

The tables are pure assumption, its possible to alter the tablespace of more tables later on, if further tables proof to store much data. Thats it, so far... until now everything runs as expected on the system, and the right locations store the data. I'll keep you posted if I need to adapt anything on the system.

Have fun!


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