Spaced Out :: 2008

The news over the last few days has been awash with items on the leaking of details of BNP members in the UK. And of course it didn’t take long for a Google mashup to be put together, although, even with the caveats that this mapped post-codes, not individual addresses it was largely misunderstood (Charles Arthur posted about this yesterday) and subsequently replaced with a “hot spot” map which is all very pretty by, well, largely meaningless. There was a nicely considered piece over at thinkwhere saying, in as many words, that on its own, the map doesn’t say too much about BNP membership as we are more interested in understanding the societal implications. This means correlating this list with measures of deprivation, population density, voting results etc etc. This can begin to identify clusters of membership and possibly why they are there (and that’s before you get in to issues of membership by occupation).

For those not familiar with the CORONA Mission, it was the original US spy satellite programme that operated from 1958-1972 (and was declassified in 1995). Of many “firsts” in satellite remote sensing, it was notably the first mission to provide photos taken from space through the launch of the camera in to a pre-selected orbit and, after image capture, the return to Earth of a capsule containing the film for retrieval by aircraft or boat. Whilst the first successful image was not acquired until 1960, it went on to capture over 800,000 images at a range of spatial resolutions.

US spy satellites are designated with a KH (for KeyHole) acronym, with CORONA ranging from KH1 to KH4. Spatial resolutions are good ranging from 7.5 m, with many at 2.75 m and some at 1.8 m. Stereo imagery was also collected for some missions. Not only does this remain “competitive” with contemporary commercial systems, but it also provides an excellent historical archive (although note that its panchromatic photography, not multi-spectral imagery). Given that Landsat-1 didn’t launch until 1972, this provides a valuable archive for a variety of applications. All the imagery are available for purchase from the USGS at $30 per frame.

And of course it wouldn’t be appropriate to conclude this blog without a brief comment on the continuing US spy satellite program. Again, Wikipedia has a nice summary of current known programmes. The successors to CORONA were initially film and then, with KH11, digital. Resolutions were commonly 15 cm (using what would appear to be a Hubble space telescope pointing at the Earth), with the expectation that the current KH13 is probably sub 5 cm.References

Wikipedia
Project CORONA - Keith Clarke, UC Santa BarbaraUSGS

Yup, that’s right its World Toilet Day! Whilst us Brits have always had a tongue-in-cheek snigger about toilet humour, typified by Adam Hart’s wonderful Thunder, Flush and Thomas Crapper and, appropriately on WTD, a piece (or piss?!) by BBC News item (from TearFund) titled Britons’ toilet pastimes revealed, there is a slightly more serious side that WaterAid/TearFund are trying to get across. Namely that 2.5B people worldwide don’t have proper sanitation. And of course:

“One gram of faeces can contain 10 million viruses, one million bacteria, 1,000 parasite cysts and 100 parasite eggs.”

At the very least have a go at playing TurdlyWinks. Go on, you know it makes sense!!

I’ve just returned from 2-days of of training in writing Python code at ESRI UK, reveling in the delights of Aylesbury. As I’ve mentioned in numerous posts, scripting is finally “back in” at ESRI and Python is the language of choice (although you can script with other languages). So much so that there is a training course on it. Don’t expect it to be an introduction to Python, although to Python is introduced. Rather it is an introduction to developing ArcGIS scripts with Python and how geoprocessing functionality is accessed. Our trainer, Rob McPherson, was excellent and very knowledgable having clearly done quite a bit of Python development. In order to get the most out of the course its worth having already used Python to do some scripting, but you don’t need to have done so.

Introductory material includes the geoprocessing environment, python, tools/environment settings and the programming model. These lay the ground for using and manipulating the functionality exposed through describe, enumeration and cursor objects. The course concludes with integrating scripts back in to ArcGIS and debugging.

Interestingly the course is delivered using PythonWin which isn’t shipped with ArcGIS (IDLE is the common IDE that accompanies Python). However it is easy to use, offers a reasonable attempt at highlighting text and offering object choices and provides a debugging environment. One of the main downsides is that you can’t kill (at least I don’t think so) a Python script that is running.

Which brings me on to the next point, namely that it seems far better to run all your own scripts from PythonWin (or IDLE) without starting up ArcGIS at all. It appears faster and more stable. In fact, avoid the IDE entirely and run it directly in Python by double-clicking on the .py file. Anyway, a good course that is well worth attending by anyone wanting to develop scripts or needing to build models. Apparently an “Advanced” course runs in the US, but is not currently available here. I hope ESRI UK can add this to their portfolio.

I’ve recently been on training courses at both Leica and ESRI UK and therefore thought it an opportune moment to compare them. And the verdict? Well, ESRI UK provide, by a significant margin, the best biscuits. No question!