Piping hot

So I made my first yahoo pipe! It collates sensor web search results and hits from del.icio.us tagged with sensor web. It still needs a bit of work – I’d like to fetch rss feeds from some of the geo-bloggers out there. Anyway, here is….. my Sensor Web Pipe.

What I did

This post is purely for my own selfish administrative reasons. We are shortly having a team meeting, and we all need to report on “What I did this year” :}. So here goes:

Started in June 2006

• Conceptualized and started the process of building the Corridor Sensor Web, a demo sensor web that is supposed to help showcase the OGC SWE services, and our work in integrating them into a working system.
  • Set up a partnership with Wavetrend, a company specializing in active RFID tags and readers. They are supplying us with temperature sensing tags and readers for the corridor at a reduced rate in return for being listed as our technology partners on whatever literature / publicity we produce.
  • This project was supposed to be completed last year, but we have now made it a student project, as I have other thing to work on. I have effectively stopped all involvement in the project and it is now worked on one day a week by a student.
• Nailed down how to install Tomcat on a gentoo linux machine, and how to install and deploy the 52North SWE services (specifically SOS, SAS, WNS) on it. Also worked on installing the software on Ubuntu boxes. Since the 52North services are tested on Windows, some of the installation steps didn’t work so well on the linux boxes, and I had to change some of their build scripts.
• Written a DBFeeder in the 52North framework, and in the process learned quite a lot about how the framework works.
• Assisted in setting up the “Nyenda Web” – a proof of concept sensor web for some engineers involved in transport services.
• Learned a lot about gentoo! – but not enough to run my PC like a pro .
• Written the Terra Cognita paper with a couple of colleagues – this has now been accepted as a book chapter for an upcoming book.
• Done nowhere near enough work mentoring our interns
• Been slightly involved in modelling our SA weather stations in Sensor ML
• Worked on the OXFramework, a desktop client by 52North for visualization of some of the OGC services
  • This was in the context of the AFIS 2 project – we are moving an existing national fire alerting system to be completely open-source and web service based
  • I have contributed some code into the main project to ensure that the web services are accessed in different threads and that the user experience is enhanced.
  • It’s been nice to use Java 1.5 – I haven’t really worked with java since 2004,so nice to update my skills a bit.
• For some months, I organised, ran and minuted our weekly team meetings. I’m quite good at this, but apparently shouldn’t be doing admin – so I had to stop.  Unfortunately, so too have the weekly meetings.

What I would like to do in the coming months:

• Kill the AFIS 2 system – get it working, demo it, bin the bugger. I’m bored silly with deploying web services.
• I’d like to work on getting the Google Maps demo working – again, this is a student project at the moment, and they are doing great stuff – this is a project to visualise where the fires have been and what the weather is across South Africa
• Review the possibilities available for GIS clients, desktop vs. browser etc. I’d like to make this a publication, even if it only ends up being an internal one – I doubt this kind of technology / literature review is of major interest to any international journals.
• Do a proper roadmap for the AFIS project
• Actually read some research papers!

I’ll edit this post a little later and link to all the relevant concepts – right now this is just a memory aid for me.

Service URLs

So we are finally getting something up and running. We have to demonstrate the service-oriented AFIS system at the end of November at GEO III as a poster paper and technical demo. Two developers from 52 North are here at the moment to help us do this.

So far we have some Sensor Observation Services (SOS’s) running, and we have Geoserver up and running on the one server, but the Web Feature Service (WFS) and the Web Map Service (WMS) both served by Geoserver don’t seem to be working. We are hoping to get a contractor in to sort these out smartly.

The Sensor Observation Services are available at:

http://ict4eo.meraka.csir.co.za:8080/WeatherSA_SOS/sos (Serves up weather information for South Africa: execute the GetCapabilities request)

and

http://ict4eo.meraka.csir.co.za:8080/AFIS_SOS/sos (Serves up hotspot information based on remotely-sensed observations: – GetCapabilites)

We haven’t yet got the SensorML descriptions of the sensors and systems properly in place – hopefully we will be able to do that soon.

Behind the times, and spatially challenged

Ok, I’m really behind the times! I just started using del.icio.us – and it is FANTASTIC!! Wow. Sometimes, you look at a technology and you think -

“Man, I wish I’d invented that”. Thus, this!

The whole non-hierarchical and tag-based classification of stuff really really impresses me! Shoo! (That’s actually also why I like wordpress!)
Anyway, my spatial challenge today stems from our ongoing attempts to make AFIS OGC-compliant. We’re using a Sensor Observation Service implementation from 52 North, and for this I have to write my own database feeder class to insert the observations into the SOS database, which of course has it’s own table-structure, that was informed by the implicit datamodel underlying the original use cases. So it’s well suited to repeated observations of particular geographical features of interest, but not to remotely-sensed data covering a large ground area.

Anyway, let me try to elucidate the current problem.
AFIS is an Advanced Fire Information System. Various satellites (Modus Terra and Aqua, and Meteosat 8 ) observe southern Africa, and pick up potential “hotspots” or fires. Various processing happens and the information product that I have access to and that my dbfeeder needs to access contains the following information about the detected hotspot:

latitude, longitude, scan, track, brightness temperature, date, time, satellite-ID, and confidence interval

Because of the various angles that the satellite passes and other remote sensing issues that I don’t understand, the latitude and longitude of the hotspot detection, which I understood to basically be a centroid of a fairly fixed-size pixel, may vary from observation to observation, even though the observed event (i.e. the fire) may be in the same place. The other problem is that Meteosat resolution is approximate 5km and the Modus satellites have a resolution of approximately 1 km.

Anyway, the usual use of the SOS is to monitor a selection of Features Of Interest (FOIs) and to obtain various observation offerings related to each one. e.g. a weather station in a particular town might be a feature of interest, and the wind speed observation might be what one is interested in. However, I don’t know a priori what my features of interest are, as a location only becomes interesting(in terms of this application) when a hotspot is detected there. So I have to generate these FOIs on the fly. They are only defined, currently, by the latitude and longitude that I retrieve from the text file. Then I attach a particular observation, complete with timestamp and brightness temperature, to the FOI, and thus, theoretically, should have a well described observation.

First I thought that I simply needed to geographically describe the fixed extent of the pixel that was being identified by the lat, long co-ordinates, but this is not fixed, and the “grids” created by such pixels may not be properly superimposed on each other, resulting in the same fire being identified with two separate features of interest, perhaps with very slightly offset centers – clearly not a satisfactory solution.

The other solution is to develop our own grid covering South Africa, and have this fixed. Probably with a resolution of 5km (or maybe 1km, so that the more precise data can also be accomodated). Then an observed hotspot would be snapped to this grid i.e. the observation would be placed within a grid square, and would be considered to be an observation relevant to the entire grid square.

I am not a database person, and particularly have absolutely no experience with spatial databases and spatially-based queries. So the niceties of how to do this have me completely befuddled. I’m currently going to have to do some hunting around to see if anyone else can give me some elegant answers to it.

Either I must have each grid-square as a FOI in the database, and simply calculate which one to link each observation to, or I must somehow calculate the geographical envelope of a grid square as it becomes relevant i.e. as a hotspot is detected.

Book good, faffing bad

Hooray! Our paper for Terra Cognita is going to be considered for inclusion in a book!

Paper: 6

Title: Fire Alerts on the Geospatial Semantic Web

————————————————————–

Dear Author

After correspondance with the editors, your paper for Terra Cognita 06

has been fast-tracked for consideration as a book chapter towards

“The Geospatial Web: How Geo-Browsers, Social Software and the Web 2.0 are Shaping the Network Society”.

http://en.know-center.at/geoweb/

If you would like your paper considered for inclusion, please follow the

submission instructions on the book’s website before 10th October.

That will be tremendously cool. So on Monday and Tuesday we hacked the paper out of LaTeX into word (*cough, splutter*) for submission to this book.

The rest of the week I spent doing fairly arb odd stuff – Read a paper, learned about JabRef (very cool) and generally talked to people about what we’re doing.