Spaced Out :: 02 2006

My third year class (Contemporary Issues in GIS) had a talk today from Giles Lane of Proboscis. Giles has a strong arts background and is driven by enabling communities to make innovative use of mobile technology. He has been involved in this sector since the late 1990s and, somewhat unusually, has worked with business, government and academia. And some of the technology deployed has involved the development of bespoke kit to support a variety of platforms for input (PDA, smartphone, interactive TV, web browser). Yet the focus is not technology led, but community led. My class certainly found this unusual and challenged their preconceptions about the the people and uses of GIS.

I attended a meeting today at the Royal Geographical Society on SPatial Literacy IN Teaching (SPLINT). It was almost a who’s who of GIS with presentations from Paul Longley (UCL), Don Janelle (UC Santa Barbara), David Rhind (City), David Maguire (ESRI), Mike Batty (UCL) and Michael Goodchild (UC Santa Barbara) amongst others. The focus of the meeting was (obviously!) spatial literacy as a result of the HEFCE funded CETL based at the University of Leicester (and shared with Nottingham and UCL). Interestingly this CETL is targeted at the taught postgraduate level. The project was “officially” launched in January with a great deal of press coverage received as a result of their “Surname Profiler”. The deliverables promise a lot that will be of use from schools, through to undergraduate and postgraduate programmes. In particular instructors will find the development of teaching aids useful and should check the SPLINT website regularly. It would be very useful if podcasts and Powerpoints of the days presentations were made available….

I had some x-y coordinates in geographic lat/long that I wanted to display with some Ordnance Survey 1:50,000 raster data (OS National Grid) as a backdrop. This point data was supplied as a comma separated text file (CSV) which you can open up (amongst other programs) in a text editor or Excel. I needed to load it in to ArcMap which unfortunately doesn’t understand CSV files for tables (at least not obviously). I used Excel to save it as a dbase IV file; it didn’t work properly and, after a bit of investigation, I found that Excel did not save the dbase file as floating point data. This time I went to Access, loaded the CSV file in to there, saved it as an Access database and then loaded that table in to Armap. Fine. You can now use the “Add X-Y Data” from the Tools menu to turn the table (with x-y coordinates) in to plottable data. That worked fine and, after saving it as a shapefile, I overlaid it on to the OS backdrop. Except all the x-y data were ~300m out. Aghhhhh! I loaded exactly the same data set in to ERDAS Imagine and, well, it worked perfectly!!! Clearly the on-the-fly reproject of the lat/long coordinates in to OSGB works in Imagine and doesn’t in ArcMap. This is very frustrating and required the conversion of the shapefile to a coverage (in order to reproject it), reprojection in to OSGB before finally reloading it. This solved the problem, but why-oh-why can’t we have proper quality control on crucial low-level operations such as this?

OK, I have succombed and bought a 1973 Series 3 Land Rover. And, well, its not particularly environmentally friendly, but its alot of fun, safe (for the occupants), ultra-reliable and cheap. The last item may be a suprise, but at over 30 years old it doesn’t pay any road tax and fully comprehensive insurance is £150 per year. This particular one has a galvanised chasis and, of course, has aluminium bodywork. So not much rusting going on there. Anyway, thought for the day is don’t drive through deep puddles quickly. Water goes over your roof and saturates the engine compartment. The result is wet electrics and a Land Rover that stalls within 30 yards.

I’ve recently been playing a little bit more with WMS (web map service), WCS (web coverage service) and WFS (web feature service) data in ArcGIS. I was interested in seeing whether I could save data streamed from a map server and after little success hit the ESRI knowledgebase. And the answer is sometimes. It would appear from the following article that you cannot save data from an map service (either ArcIMS or WMS) as they are simply. However if you want to save vector data (e.g. from a WFS stream) then it should be possible by selecting the features, copying them to a new layer and exporting it as a shapefile. At the moment I donot think that WCS is supported but it would be nice to be corrected on this one (which means no saving of raster data). All somewhat longwinded and not what I expected. If anyone has further experiences or ideas I would be very interested.