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The ache of almost being in the sweet spot September 14, 2010

Posted by grimmeister in Geoinformatics.

Freshly back from another inspiring FOSS4G, Barcelona, I returned full of enthusiasm to slay a particular dragon of mine:

Our research organisation is a long term ESRI shop, where geographers, ecologists, planners, statisticians, remote sensing specialists and other assorted scientists have been happily using ArcGIS/INFO/View Desktop software for many moons. It is a semi-pointless battle to convince older users in particular of any benefits of using FOSS4G tools on the desktop – they have tools that they know well and perform the necessary tasks (even if we are talking venerable tools like ArcView 3.x). Convenience is a huge factor for such users, who do not necessarily consider themselves as GIS practioners in the first place, and will simply not be interested in learning a whole new GIS tool.

On the other hand, our organisation is supposed to push boundaries with FOSS in a country where we have a mandated FOSS policy. Now, there are a number of researchers who happen to run forms of Linux or who are comfortable with FOSS4G softwares, and are quite excited by the possibilites for pushing such software into all sort of nooks, crannies and other experimental places in conjunction with other FOSS apps, libraries and components.

In the middle of this situation, the organisation is trying to implement an enterprise SDI, from a modest budget that must fund a number of floating and single use ArcView and ArcInfo licenses. Since the folk who are actually running the implementation process are 1) not really GIS users or 2) have not tasted the yummy FOSS4G Kool Aid or 3) are from the IT department where certification and promises of support are paramount, the convenient thing to do has been to let the local ESRI guys lead the implementation thought process. The wisened amongst you will recognise the VAR wet dream. Indeed, the ArcGIS Server was shipped before you could say boo! to a goose. So the plan was an enterprise ArcSDE spatial database running on Oracle, serving all its wonderful goodness to our licensed Arc* users and the occasional WMS through ArcGIS Server. Sweet. Except for a nagging issue (well, I would call it that)….

Like, umm, what about us?!! The non-ESRI desktop users?!!! You know, the slightly geekier, poorer, maybe more experimental types???!! Are we to sit on the edge of the SDI hoping for a WFS tidbit (if the implementation of ArcGIS server even bothers with such a thing). Of course, it would be easy enough to run a parallel SDI on a FOSS stack, but that is not particularly constructive is it? Luckily Oracle to the rescue…

More precisely, its licensing fee structure. The expense of it. Too much for our modestly funded SDI effort, considering our need to share spatial data, originating in Oracle, over the web. Now, a while ago, I had sown the seed of a possible PostGIS backed ArcSDE for our enterprise, and had even experimented with such a configuration, concluding that we may just get by with it if limited editing/ upload capability was allowed for FOSS4G type clients – at least we would be able to work with shared read-only data and happily serve up W*S’s through GeoServer/MapServer.

ArcCatalog - Openlayers off Geoserver - QGIS direct read of SDE on PostGIS

So, re-enter me, fresh from FOSS4G, keen to see if PostGIS could be dropped into the enterprise, just like that!

Some annoying realities intruded to burst my wee little bubble. The PostGIS/SDE 9.3 combination is only supported on 32 bit Windows machines, and 32 bit Enterprise Linux flavours. I have been enjoying the bounteous riches of 64 bit Ubuntu (that really free OS) for some years now , so was a bit taken aback, worsened by the discovery that SDE 9.3 is only supported on Postgres 8.3.0 with PostGIS 1.3.2.  http://wikis.esri.com/wiki/display/ag93bsr/ArcSDE+PostgreSQL+Database+Requirements. No Prepared Geometries, Cascaded Unions, Geography Types, Window Queries, etc . I feel this is very weak support, but hey, at the least, we could still have PostGIS geometries, for what they are worth.

But then I let a sneaking suspicion re-enter my mind: nobody in the organisation really makes use of the powerful features of SDE, like versioning, geodatabase modelling, multi-user editing, etc, so why do we need ArcSDE/ArcGIS Server in the first place….? To test this, we met with a user whose research group potentially used geodatabases more fully. Her response inflated and deflated my mood at the same time. It turned out that they were not even using any enterprise provided database facilities, determining that they were not performant. Instead, the limited amount of geodatabase activity they undertook used a shared file geodatabase structure, from which they were publishing WMS offerings via ArcGIS Server. I left the meeting energised by the possibility that the road was open to replacing (rather than tweaking) ArcSDE and ArcGIS Server with PostGIS and Geoserver, but a bit concerned that a long road lay ahead to convince users to take advantage of shared SDI components.

Seeing an open road, and a challenge, I dug around to see if there is a way to make this whole enterprise SDI lark a non-zero sum game. ZigGis seems to be the best (and good)  candidate to get ArcGIS clients to access PostGIS directly. This sounded really positive – the existence of a sweet spot, where everyone could be happy! What is more, it looks like ZigGIS is going Open Source again, potentially reducing the licensing overhead against our limited budget. Alas, we really need ZigGIS 3 – the sweet spot receded with the realisation that ZigGIS would not currently be useful to Arc* users primarily since it does not have ArcCatalog functionality . So, you may ask, what about funding the ZigGIS project in order to speed up its work tords a 3.0 release?  Good Point indeed! This is going to be fun trying to build up a business case for our organisation to fund development, when all the IT services want is risk reduction and guarantees. Which leads me to another reason why I ache so much today – a supported PostGIS/Geoserver/Desktop Client stack, so coveted by the IT minions, would actually cost a similar amount to an ESRI stack. Now, I can still think of a lot of reasons why such a stack offers more value (read replication, flexibility, wide usage of standards, etc), but I wonder to what extent this sweet spot, winners all around scenario will seem compelling enough to our moneybags people…

You may have heard this:

“There we were, two against two thousand – boy, did we take those two guys out!”

I feel like one of the two guys, lined up against a all sorts of obstacles (technical, organisational, lack of interest, financial, timing) before there is any view of what seems a sweet spot.

Ah well, nothing ventured and all that…

Revving up Geoserver on Ubuntu HH LTS November 10, 2008

Posted by grimmeister in Geoinformatics.
Tags: ,

Given my setup described at revisiting-geoserver-on-ubuntu
, I am slowly learning (with Tim Sutton) good and weird lessons on how to make geoserver really punch out those services…

No question, you have to do a few things. Geoserver out of the box is relatively minimalist. So a few things need attention, many outlined in the *geoserver in a production environment pages* of the website.

1) Make sure you are using the server jvm.

UPDATE: see Andrea’s comments – the server VM automatically kicks in if you have a server class machine, and configures resource allocation similar to what is described in point 2.

Many docs, including those at Geoserver suggest using a -server flag for the tomcat daemon. This is rather mystifying to myself and others, because Tomcat will not start on our systems if we have this flag set. So my conclusion is that the -server flag is inbuilt into server class machines, or in the Ubuntu 64 bit environment, it is just not available.

I suspect that the kind folk at Ubuntu have distributed the various server flavours with the server jvm as default. To check, type at prompt:

java -server -version

you should receive back something like :

java version "1.6.0_06"
Java(TM) SE Runtime Environment (build 1.6.0_06-b02)
Java HotSpot(TM) 64-Bit Server VM (build 10.0-b22, mixed mode)

If you get this, you will notice in the file /usr/lib/jvm/java-6-sun- that the server option is default.

If you do not get this message , it is likely that you have not got the sun jdk installed for your server, so fetch and install it, make sure the jdk /bin is first to be found on the path, then repeat the above test.

So the question you really need to answer, is whether /usr/bin/jsvc (commons-daemon on Debian/Ubuntu) is hitting the appropriate JVM.

A question that bothers me a bit is whether there is even a -server flag on 64 bit Ubuntu. This configuration step may be pointless. Seems odd, but my readings have hinted that it is not an option on AMD64 architectures. Given Ubuntu 64 bit seems to work on X86 and AMD64 systems, is it possible that an artifact is a missing -server flag

A little bit vague I know, but may give you enough of a hint to get it working fully.

2) Throw resources at Tomcat

From the get-go give tomcat lots of resources (depending on what else is running on your system). Do this in your tomcat daemon script ( /etc/init.d/tomcat5.5) JAVA_OPTS section. JAVA_OPTS="-Djava.awt.headless=true -Xms144m -Xmx768M -XX:SoftRefLRUPolicyMSPerMB=36000 -XX:MaxPermSize=256m -XX:XX:+UseParallelGC" So, I have set the minimum heap size to 144Mb of memory, maxing out at 768Mb and giving the JVM space to move. I have increased the perm gen space to 256 Mb to aid in classloading and have made use of my multiprocessor setup for garbage collection. There are loads of options available – I am certainly not sure if I am properly optimised here at all.

3) Sessions

I have been grappling a fair amount with a particular issue around Tomcat sessions spiralling out of
control for the geoserver context.

So, make sure (if you are using tomcat, and this seems to be a problem) that you add or modify
the /webapps/geoserver/WEB-INF/web.xml file to include:


This prevents sessions from being kept alive when idle for more than a
minute. Geoserver does not need them apparently. Be aware that you should probably only do this once your geoserver config is happy – otherwise you will be logging in a lot :-(
4) Logging

make sure to set the log level to PRODUCTION-LOGGING.properties in the server part of the config.

5) Tile Cache

If you are serving WMS, put a tile cache of some variety up in order to reduce the load on the database and geoserver. MetaCarta’s TileCache, GeoWebCache, OSCache, even something like Squid could be used. I have not set it up a tile cache yet, but will add details if and when when I do so (my WMS’s data tend to change quite a lot)

6) Apache Portable Run Time library with Tomcat

The use of this library allows certain aspects of tomcat to be enhanced, with performance gains of 10% or so reported. I guess it would depend on what you were serving!

Binaries for this library can be found, but it is better to compile from source ( with some help from http://www.liferay.com/web/guest/community/wiki/-/wiki/Main/Tomcat+Native+Library ).

Make sure that you have the libssl-dev and libapr1-dev packages installed ( sudo apt-get install libssl-dev libapr1-dev)

http://apache.seekmeup.com/tomcat/tomcat-connectors/native/1.1.15/source/tomcat-native-1.1.15-src.tar.gz is some source code

Extract the tarball of the tomcat native lib (tar -xvzf tomcat-native.tar.gz)

cd tomcat-native-1.1.5/jni/native

Configure ./configure --with-apr=/usr --with-java-home=/usr/lib/jvm/java-6-sun- (or wherever your jdk lives)

Make and install (sudo make && sudo make install) – generates the library and symlinks in /usr/local/apr/lib

Change to the system library folder ( cd /usr/lib )

Make a symlink to the library  (sudo ln -s /usr/local/apr/lib/libtcnative-1.so libtcnative-1.so)

Edit ${TOMCAT_HOME}/bin/catalina.sh adding the following lines somewhere before java is executed ( LD_LIBRARY_PATH=/usr/lib:$LD_LIBRARY_PATH export LD_LIBRARY_PATH )

Restart Tomcat and make sure to check your logs for success or failure. It seems that failure may likely result from problems with IPv6 enabled machines. Disable IPv6 ( edit /etc/modprobe.d/aliases and change the linealias net-pf-10 ipv6toalias net-pf-10 off ipv6 and reboot ) if you can.

7) Native JAI rather than the pure java JAI

This applies in particular if one is attempting to serve raster data, perhaps some satellite imagery but per Andrea’s comment is valuable for improving WMS generation too. So:

fetch the libraries. I got myself the ones from http://download.java.net/media/jai/builds/release/1_1_3/jai-1_1_3-lib-linux-amd64.tar.gz

After unpacking the tarball, I copied the 3 jar files:

sudo cp jai-1_1_3/lib/*.jar  /usr/lib/jvm/java-6-sun-

and the shared library:

sudo cp jai-1_1_3/lib/libmlib_jai.so  /usr/lib/jvm/java-6-sun-

then restarted Tomcat. JAI appears as available on the Geoserver Admin page.

Well Done USA November 5, 2008

Posted by grimmeister in Uncategorized.
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I think many folk in South Africa were most pleased to see Barack Obama become President-Elect. I listened in on his victory speech and was really overwhelmed by it (I have not heard him speak too many times, so maybe it is his normal style). It felt Mandela-esque to me – wise, kind, rounded yet persuasive. It struck me that even if the current state of the world prevents him from achieving his visions, his call to people to change the way the see things is what is most compelling. He seems to make politics just a little more personal, as if a small person can do big things.

Yes Please!

Revisiting Geoserver on Ubuntu July 28, 2008

Posted by grimmeister in Geoinformatics.

After a year or so of running Geoserver 1.5.x in a prototyping environment, I have run through the process of getting Geoserver 1.6.4 running in Ubuntu 8.04 a.k.a Hardy Heron production environment.

The overall view: it is dead easy now, with less fiddling necessary. So the steps in the process

Apache Tomcat/5.5
Sun jdk 1.6.0_06-b02
Linux 2.6.24-16-server kernel
64 bit Architecture

1) sudo apt-get install sun-java6-jdk.
Given that sun jdk installed, make sure its jvm is the default jvm
sudo update-alternatives --config java
choose the sun option

2)Tomcat is a bit quirky on Ubuntu

2.1)if not installed, do:
sudo apt-get install tomcat5.5 tomcat5.5-admin tomcat5.5-webapps

2.2)Configure Tomcat for the Java JDK. Edit /etc/default/tomcat5.5, uncommenting this line:

2.3)Set some permissions:
cd /var/lib/tomcat5.5/
sudo chown -R tomcat55:tomcat55 logs work
sudo chown tomcat55:tomcat55 /usr/share/tomcat5.5

2.4)Change service port to 8080 (default is 8180) in /etc/tomcat5.5/server.xml if need be

2.5)Change the users and passwords for working with tomcat, tomcat admin and tomcat manager in /var/lib/tomcat5.5/conf/tomcat-users.xml
Advice seems to be to get a separate admin user with roles {admin, manager,tomcat}

2.6) No more need to fiddle with the catalina.out issue – seems to have been fixed

So, to Geoserver…

1) We need to have the ability to serve OGC standard WFS, WMS and potentially WCS. We know the Geoserver tool works as we have been serving WMS, WFS and very large WCS’s through it.

1.1) Download the .war file in a zip file from the Geoserver website. We are using 1.6.4. Extract .war file

1.2) Deploy the .war file from the Tomcat Manager page. This will take place okay, but Geoserver will not be able to start, for Tomcat on Ubuntu (well, as provided by Ubuntu in the repositories) is by default tightly locked down.

1.3) No need seems to exist to create a geoserver.policy file anymore. On 8.04, it would appear that such a file would have to live in /etc/tomcat-5.5/conf/policy.d directory, but its presence completely prevented Tomcat from even starting, so I left it out

1.4) One still needs to open the /var/lib/tomcat5.5/conf/policy.d/04webapps.policy document and add a line to it granting looser security permissions:
permission java.security.AllPermission;

Then restart Tomcat and get cracking with setting up your data environment or migrating it across to the new version of Geoserver.

Green Housing Complexes November 23, 2007

Posted by grimmeister in Uncategorized.
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In South Africa, there is a housing phenomenon called “complexes”. These commonly occur in the form of several storey townhouses; separate, but closely packed bungalows {simplexes}; or double storey bungalows {duplexes}.  Complexes characteristically exist behind a large, electric fence topped wall, creating in effect, a walled community. Usually, complexes are built on greenfield sites, sometimes on brownfield sites (like near landfills, in some obnoxious cases), or  on previously huge suburban properties which have been subdivided. The image below (1mb), of a middle class suburban part of northern Johannesburg  demonstrates the pattern quite well (thanks Google Earth, I can see my car!).

suburban pattern

They are increasingly pervasive for reasons of 1) perceived security, 2) convenience and 3) cost. More cynically, land developers also push the building of such places for reasons of profit, driven by own-to-rent speculators. The kind of title under which homeowners often acquire them is ‘sectional title’. I am definitely no boffin when it comes to such legal concepts, but I see several obvious implications of such title:

  • It is difficult to change the structure of such homes, especially external;
  • Any changes have to be agreed to by ‘body corporates’ ;
  • There is perceived value in keeping up standards of appearance;

I started thinking about how such complexes could be  made more environmentally friendly and about how difficult this would be to achieve. I will discuss a few things in context of the earlier image.

On the positive side, as far as I understand it,  complexes concentrate people and make it easier in theory to supply services to, like roads, water, sewerage and power. If everyone aspired to or expected a suburban house like can be seen on the right hand side of the picture, a city like Joburg would be spreading at a scarier rate than it already is, threatening the peri-urban fringe and making us all even more reliant on cars than we already are. A reasonably spacious (often older) complex is appx three times denser in terms of houses than a similar sized patch of suburban houses.

There is a flipside to some of these issues and a whole host of others. The increased densification puts pressure on existing services – this area is subject to power blackouts, the roads are more congested and damaged by the increased flow of traffic, and the water supply has had to be re-engineered. In the push to house people, the biodiversity of the area (rich, by the way – try bullfrogs and grassland birds for a wee little snifter) is put under huge pressure, and the greenbelt surrounding the city is eroded,leading to produce having to be shipped in from further away, thereby increasing transport costs. Furthermore, the South African housing construction idiom is bricks and concrete. Termites would annihilate untreated wooden structures. The environmental impact of this is the transport costs of bringing in construction materials and the energy usage in producing them. In addition, the impermeable surface of a given area is increased, leading to increased and more acute runoff, a real concern given Joburg’s rainfall arrives in the form of torrential thunderstorms.

So, what could be done? Solutions seem  so simple. I am not sure they are, as I do not understand  all the engineering and economics behind the built environment, but here goes a few obvious ideas.

1.) Google’s data suppliers would have few issues in getting satellite imagery. Aside from afternoon and evening thunderstorms, the sun beats down strongly, happily  and abundantly. With great conviction, I can opine that none of the complexes in the image use solar energy in a planned way. One or two homeowners may have solar heated swimming pools, but few would have solar geysers. Look at all the roof space – where are the solar panels?

2.) Where are the rainwater tanks to capture runoff from all these roofs? People water their gardens and fill their pools from their taps. Surely it makes environmental sense to reduce runoff and actually use rainwater domestically?

3.) How about this – can’t a complex have a vegetable garden? This not only provides for some food requirements, but imagine the possibilities for educating children about farming, nature and one of life’s virtues, patience. Also, I suspect a vegetable garden, if properly designed, could provide a sanctuary for people. Most of these complexes have some common land, often barely utilised. Grow some crops I say!!! Reduce our reliance on vegetables grown far away and heaved in by smelly trucks. Along similar lines, what about a complex compost heap and/or earthworm farm for recycling organic material. This would provide goodness for the veggie patch and for peoples gardens.

4.) This is far fetched, but I know it is possible, as a friend in the area is doing exactly this with an addition to his house – build houses out of local material using sustainable building practices (rammed earth walling for e.g.)

5.) Put double glazed windows and roof insulation in the houses to reduce use of aircon in summer and heaters in winter.

I am sure there are other ideas.

Trouble is, generating the will amongst homeowners, land developers, and body corporates seems a huge mountain to climb. Will a body corporate allow homeowners to install solar panels/ geysers, windmills, watertanks, double-glazed windows etc, given that sectional title almost implies an ‘all-for-one, one-for-all’ approach? Tell the average homewoner that they could quite happily have a solid house built of sand and mud largely sourced from the earth turned over to build that very house and you will surely get a strange questioning look at the least. Forget most property developers! The chase for profit means that the complexes need to be built as rapidly as possible using the means that are known to builders (bricks and concrete). As for a vegetable garden – well, wouldn’t that mess up the nice symmetry of the lawn and attract rats? Heaven forbid that a complex have a compost heap!

Complexes provide a  small opportunity to develop  some of the more ecologically friendly aspects of community living – I am pessimistic about the chances of this happening though. I will report on how some of these ideas are received, as I have just become a trustee of my own body corporate. Some socialist leaning friends of mine found themselves working for bastions of capitalism in the form of the business press. When queried about this apparent mismatch, they said they would fight the revolution from within, and always wear red socks to work. Can I fight the green complex revolution from within and wear 100% organic cotton socks? Who knows, but at least the socks are easy.

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Ubuntu Gutsy 64 bit GIS Workstation Theme part 1 November 1, 2007

Posted by grimmeister in Geoinformatics.
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I have a nice shiny new 64 bit workstation:

  • Dell Precision 690
  • 2 x Xeon 3Ghz cpu’s
  • 4Gb RAM
  • 2 x 250 Gb Seagate SCSI harddrives
  • NVIDIA 256 mb graphics card


which I populated after some deliberation – I haven’t owned a 64 bit machine before – with Ubuntu Gusty Gibbon. The result – a rather crisp workstation!!!

I naturally installed qgis out of the Ubuntu repositories but with the late October release of QGIS 0.9.0, I felt it was time to check out the latest and greatest. Following the always useful advice of Matt Perry, in this case at Turning Ubuntu Into a GIS workstation, I downloaded the qgis release binaries for Ubuntu Gutsy and, full of expectation, tried to run them. Cue the sound of deflating expectations….

Of course, the binaries were not compiled for the 64bit architecture. So, I braved the world of cmaking QGIS, ‘cos I really want version 0.9.0. with Python bindings and GRASS capability. This description is best read in conjunction with the detailed readme available with the source code – mainly it is just a simple version…
So, to the first part of the build process as outlined on the QGIS wiki: cmake .

  • The usual suspects (depending on requirements) need to be present on your system – Proj, GEOS, GDAL, PostgreSQL and GRASS
  • Additional common components include Expat and Sqlite3 – get them from the repositories
  • Make sure you have a C compiler installed – well, it is unlikely you won’t have one…
  • Make sure you have a C++ compiler installed ( I installed G++ 4.1 from the repositories )
  • Make sure you have flex and bison installed ( again, I got them from the repositories )
  • Make sure you have the GNU Scientific Libraries installed (gsl-bin, libgsl0, libgsl0-dev from the repositories)
  • Get the sip Python/C++ bindings generator (sip4 in the repository, plus, for good measure, I installed the python-sip4 and python-sip4-dev libraries).
  • Ensure the presence of a whole bunch of QT components like qmake, which is found in the libqt4-dev library. This library comes with a bunch of QT and related dependencies – that is a set of relationships I have no understanding of. Basically, you need to have QT installed. The qgis readme is the place to source these dependencies. If they are not on your system, the download is reasonably large.

And so cmake . finishes and one has the build files generated and configured.

So, to the second part of the build process, the make and make install. This went fine, once I had returned from a ramble into QT country. I am not sure why the readme wants one to install certain libraries such as resolvconf.

I am sure the build files could be more optimised for a Debian install, but that is about a thousand steps too far for me at this point – I’ll accept the default graciously.

And off we go – QGIS on Ubuntu Gutsy on 64 bit workstation. Looks great so far – most obvious diffrences are the much larger array of GRASS tools available and the existence of a WFS plugin.

Thoughts on my boy September 18, 2007

Posted by grimmeister in The spectrum.
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So, there I am, feeling alright with the world, having enjoyed a dinner prepared by my wife, who was feeling rather amused by her ‘clumsy day’ – I watched her drop all sorts of things and then stub her toe on a wall. I was sitting outside in the inky Johannesburg early summer evening (which is a truly marvelous thing indeed), listening to the crickets and other nocturnal insects and generally reflecting on my day. I was thinking about all the fun I had just had with my 4 year old lad, Connor J. He was having a complete hoot in his tyre swing, leaning back to watch the trees and then catching me out when I stopped singing nonsense rhymes to him. I could hardly prise him off the swing to go and take his bath, which he just loves having. We spent bathtime catching the little glittery clams, dolphins, whales, stars and tortoises that are mixed in with the bubble-bath. At dinner, Connor tried – unsuccesfully of course – to scrounge more tomato sauce for his chips before getting ants-in-his-pants, relievable only by getting down from the dinner table, naturally. Later, we had a session playing minesweep and some of the excellent childsplay games (I am convinced Connor is learning to type!) on the computer. Connor eventually drifted off to sleep after humming a couple of tunes to himself.

My mind somehow cast itself back to a time when we were still pregnant with Connor and went to a talk on vaccinations delivered by a cranio-sacral therapist guy. Now, the audience was hanging onto this fellah’s every word as if he actually knew what he was talking about. The medical doctor invited to give an ‘establishment’ view stuck out like a sore thumb, looking a bit sheepish in the face of the diatribe against vaccines. He tried pretty hard when his turn came to convince the audience that vaccinations are actually a *good thing*, but the audience generally was not listening, prefering instead to get sucked into the whirl of anecdotes, pseudo-science and assorted claptrap that the melodramatic altie therapist was spewing forth. I realise now that he was laying on a thick story that ultimately played to peoples fears of vaccines causing developmental delays and disturbances in their children and how these evil conditions can be avoided if only we bravely rebel against vaccines.

My thoughts swung back to Connor. He has only recently started his vaccination program and it seems to be going just fine. The thing is, well, Connor is autistic and epileptic and has been from his time in the womb, I am sure. If I were to be honest with myself, I would say that I was influenced by the cranio-sacral chappie a bit, but ultimately we did the right thing by holding off on the vaccines – we just did not know what we were dealing with in terms of Connor. But that is not my point. Rather, I was wondering to myself why people resort to scaremongering around things like autism. Why is it that people would prefer not to have children like my astonishing Connor J around?


RWC ’07 Kicks off September 7, 2007

Posted by grimmeister in Uncategorized.
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The SouthernTip is rugby land. The SouthernTip is also about to be rugby mad, for today is the start of the Rugby World Cup in France. South Africa seems to me to have a great chance of doing well. Some folk think that anything other than a victory in the finals represents failure. Sure, not winning it will be disappointing, but the level of competition is such that 1 of 4 sides is quite capable of scooping it and we Saffas should try not to become too glum if the trophy does not come this way.

So, I thought about a (very subjective) wailing-and-gnashing-of-teeth-ometer metric (WAGOTOM) that could be applied to the various nations – basically, how deep will the depression be in each country should their chosen warriors fail to deliver a golden pot at the end of October.

Each nation to be rated on a scale of 1 to 10 on the following:

  1. Supporter Expectations
  2. Quality of Team
  3. Belief of Nation in Divine Right to Win RWC
  4. The Draw

Categories of WAGATOM (hey, this actually touches on some serious issues):

  1. National Disintegration and Moral Decay {35-40} – Economic reverberations felt, increased domestic violence, increased substance abuse, threats to the health of RWC participants even after vitriolic sackings have taken place, absenteeism, inability to do anything else other than morbidly dissect what could have been, front page of newspaper stuff for a good few weeks
  2. Woe is Us {26-34} – Enhanced levels of moping for a period longer than a week, absenteesim, minor turning to substances for a period of about a week, lengthy periods of dissecting the results – with much blaming of the referees, front-page news for a couple of days, sackings of RWC participants with associated blame attached
  3. Sporting Disappointment{15-25} – Two or three days of moping, substance induced hangovers, sports-pages headlines after initial front page burst, retirements and movements of RWC participants make the news, no economic effects other than lengthy and dreary discussions around the coffee pot
  4. Minor Sporting Interest {7-14} – Characterised by comments such as ‘I heard we lost the big rugby game – too bad, I am sure they tried hard’, featured on sports pages (possibly as a lead story, possibly not). Strangely, this WAGATOM can possibly still be felt in nations where the general feeling is one of Woe or Disintegration, but is restricted in the most part to womenfolk
  5. What is Rugby? {0-6} – zilch interest, national warriors might just as well have been having dentistry done, perhaps a small entry somewhere in the sports pages.

So, the maximum value of the WAGATOM for any country is 40, minimum is 4. Where do you think the nations fall and why? Lets try two extremes:

  • Portugal {4}
    1. Supporters? Are there any? {1}
    2. Name me one of the team members, I dare you… {1}
    3. What exactly is rugby? Must be some sort of wierd game played in the English colonies {1}
    4. Will lose (messily) to all of New Zealand, Italy, Scotland and will have a tussle with the Romanians only to succumb to the big chaps from the Carpathians. {1}
  • New Zealand {37}
    1. Nothing less than clear victory, obtained with style, power and verve, in a dramatic final against one of the old foes like SA, Aussie or England. All NZ fans know that NZ always beats France, but it would nevertheless be satisfactory form to beat France heavily in front of their home crowds {10}
    2. You could populate a World’s Best XV with at least half the All Black starting lineup – these guys are big names and are expected to perform (including suitably gushing pre-game, on-the-field micturation)! {9}
    3. Our team is the best team, we have been robbed for the last 20 years, the Cup is coming come this year, to where it belongs, and no ugly Saffa, stinking French or cheating Aussie team should even try to stand in the way of this Chosen Path {10}
    4. Will club Portugal, Italy, Scotland and Romania in the pool games. There will be hundreds of points scored and multitudes of tries. The Quarter-finals should see a resounding win against a weakened and demoralised England. Then, a semi-final face off with their RWC nemesis, Australia, followed by a date with SA or France in the final, where the big occasion could see any of these two raise their games to stratospheric heights. In a nutshell, the draw gets pretty tough for them after an easy start! {8}


FOSS4G2008 coming to the Southern Tip August 28, 2007

Posted by grimmeister in Geoinformatics.
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A couple of weeks ago, South Africa was awarded the Free and Open Source Software for Geospatial Conference for 2008. It will be hosted in Cape Town in September. This is really good news and, I feel, a bold decision from OSGEO. I believe, for the first time, they will be moving the conference away from the core developer community of FOSS4G.

However, the timing is great to bring it to SA because of rapidly increasing interest and investment in FOSS, driven by stated government policy to prioritise its usage. There seem to be three drivers for this: a perception of reduced cost; the importance of FOSS in bridging the ‘Digital Divide’; and FOSS’s role in increasing innovation and ICT literacy.

To me, the latter two are the themes that will enliven FOSS4G2008 in Cape Town, though there will without a doubt be much carping about costs. South Africa has a little bit of a tradition of innovation in the geoinformatics/ GIS space – off the top of my head I can point to Danie Krige of kriging fame, PlanetGIS and the ReGIS software, parts of which were later incorporated into Autodesk’s products. It would be interesting to know of other GI innovaters/innovations originating from SA.

The general reality on the ground in SA is the strong dominance of ESRI. This in and of itself is not a *bad thing* exactly, as the ESRI software is pretty darn good, but one effect has been the creation of a nation of ‘ArcView jockeys’, who know what buttons to press without necessarily understanding anything of what is happening under the hood. With exceptions, of course, it is really a mentality of “let ESRI understand what needs to be done and we will just buy the software/extension/script/service pack”. Convenient, yes; innovative, no; expensive, certainly – the dollar stretches a long way in SA. Well, hopefully FOSS4G2008 should help to perk up a few minds locally to the ocean of potential lying in the FOSS4G stacks.

As for the FOSS4G2008 overseas punters , well Cape Town is really rather nice. The effect of such a statement on a Capetonian is a bit like the effect of telling a Vancouverite the same thing. Cue spluttering indignation… Whatever. There will certainly be some interesting sights, sounds and experiences to be enjoyed. I hope it turns out to be a very hands-on, fun and enriching conference.


Two pairs of eyes August 14, 2007

Posted by grimmeister in Geoinformatics.
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I am writing some Python code using the OGR libary. It essentially ingests text files dropped onto a filesystem and turns them into features amongst other things. The data provided are x and y coordinates and some attributes. So, no problem, turn them into points. Trouble is, I needed to turn the points into square buffers of size 3km. I built a buffering routine but it was behaving oddly, generating buffers for all text files in a given directory on one pass, but only generating buffers for one text file on another pass. Eventually, the problem emerged: segmentation fault. I had been pulling my hair out for days trying to understand the problem.

The thing is, one gets commited to one’s code, trying to adjust it in tiny bits and pieces, rather than trying something new. This is where a second pair of eyes comes in. A second person overlooking your work does not have any emotional?? attachment to it and can happily suggest throwing code out and trying a new approach. End result: no more segmentation fault and a program that runs much more efficiently. Thanks Shriram!


More hair-pulling out! As my colleague Lee points out, if you want to know what is really going on in your code, don’t use wrappers! It took me hours to figure out that OGR (admittedly, a rather older version thereof), when used with its Python bindings, does not seem to enjoy having too many OGR objects used within a single method/routine. Thusly, in my method that ultimately buffers a point geometry and stores the new polygon geometry in a shapefile, I was unable to do a ‘contains’ test on the point geometry without getting weird and woolly segmentation faults and glibc double-linked list errors. This geometry test had to be done in a completely different part of the application.

Now, Lee suggested I rewrite the geometry testing code. The heresy of it!! I still like OGR and put it down to my own inexperience with the libraries. There is more chance of our *illustrious* President firing our unspeakable Health Minister than there is of me writing a usable geometry library. Those of you in the know about current SA politics will agree on the futility of it…



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