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Dan Karran

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The simplicity of installing software on Linux

I love the simplicity of installing open source software on a Linux box.

I had barely touched Linux (or a *nix command line) before I started in my current job, ignoring a few months with a little use of the Terminal on my iBook. Since being here though, I have picked up quite a bit as I've gone along. It took a little while to get used to at first, but it's sort of a second nature now - when it comes to some things, at least - to move over to the command line and do what I need to do there. It's very handy when developing software and working with revision control systems just to be able to do what you want by typing a few commands instead of doing it with the mouse through the graphical interface.

Installing new software is a breeze on Kubuntu (as it is on other Linux distributions) - simply type sudo apt-get install [name of software] and it'll do all the work for you. No need to go to a website, download it, unzip it and double click to install.

I needed to start drawing a diagram, so I asked my colleagues for a recommendation. They suggested Dia, so I went off and installed it and had the first cut of the diagram ready to go within half an hour.

Posted in , at 1:34 PM on Tuesday 20 February 2007 | Comments (3)
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Russian 1:500,000 mapping of the Isle of Man

isleofman-russian500k.jpg

Before the fall of the Soviet Union, they put a lot of energy into mapping the rest of the world, at small scales like the section of map above, but also at larger scales for certain places of key interest to the Soviet government at the time.

The more detailed larger scale maps were deemed by the Ordnance Survey to be copies of British mapping and so although the maps are copyright free (Russia didn't believe in copyright when these maps were being produced) it is questionable as to whether they can be reused in the UK*.

isleofman-russian500k-crop.jpgYou can read much fascinating information about Soviet mapping on John Davies' Soviet Military Maps of Britain site, but I just wanted to share this interesting Soviet cartography of the Isle of Man with names transposed into Russian.

The original map image is available from the Poehali website.


* The OS specifically call out 1:25000, 1:50000 and 1:100000 mapping, so I hope posting this 1:500000 map extract of the Isle of Man won't cause any problems.

Posted in , at 12:30 AM on Monday 19 February 2007 | Comments (0)
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Maps of Stuttgart

Landkarte von Schwarzwald
Taken at Buechsenstrasse 54, Stuttgart, Baden-Wuerttemberg, 48°46' 45" N, 9°10' 15" E

The state surveying office (Landesvermessungsamt Baden-Wuerttemberg) here in Stuttgart has a display on the outside of their building showing satellite imagery covering the length of the Rhein with a number of examples of maps from the places across the region over time. This old map shows some of the area around the Black Forest, or Schwarzwald, just south of here.

Posted in , , at 6:51 PM on Sunday 18 February 2007 | Comments (1)
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GeoRSS in the wild

I've been working today to try and get Drupal's GeoRSS module listening to more than just the deprecated Aggregator2 module to extract geographic locations from aggregated feed items.

The Feedparser module is the next on the list to support and as far as I'm aware is the only one of Drupal's aggregation modules to use an external parsing library, SimplePie. By using an external library it means that we don't need to deal with the sometimes complex task of parsing different types of feeds on the Drupal side, which is a bonus because efforts can be concentrated elsewhere whilst keeping the code nice and simple.

SimplePie is still in development stages but appears to have a good community around it as well as a couple of active developers. They're gearing up to their 1.0 release which includes functions to extract geodata from feeds using the W3C Geo and GeoRSS Simple encodings, the former being the most widespread of methods at present and the latter the one we should be moving towards using.

SimplePie's code is very much based around namespaces (e.g., xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"), which a lot of other aggregator systems will often disregard in favour of the simpler method of parsing out just the individual element names from that vocabulary (e.g., geo:lat or geo:long) to identify the tags. Now that namespaces have suddenly become important (at least for SimplePie's code to work), it's interesting to see how easily overlooked they have been in the past.

Take, for example, the Geograph GeoRSS feed of their latest photos: they had a trailing slash after the GeoRSS namespace URI (http://www.georss.org/georss/ instead of http://www.georss.org/georss as it's defined in the spec). It was there because many namespaces do have the trailing slash, and simply left in by mistake, but because that's not what SimplePie was expecting, it didn't pick up the geodata in the feed. It's been fixed now (Thanks for the quick fix Barry!). There is also the case of the Flickr GeoRSS feeds that use the wrong namespace URI (using the one for W3C Geo instead of the GeoRSS one). Hopefully Rev Dan Catt or someone else at Yahoo will be able to fix that one up.

Even besides namespaces, some elements are often misused, and possibly the most widespread of those is geo:lon which should in fact be geo:long according to the spec. SimplePie doesn't understand the non-standard one and so can't pull the location information out of the feed. In this case, because it is so widespread, the parsing code should probably be extended to look for the non-standard element if it can't find the standard one.

Anyway, just some random observations of GeoRSS in the wild and how what seem like the smallest of differences can mean that the embedded location information will simply be missed by feed consumers.

If you've got a GeoRSS feed from your site, please do the right thing and make sure it's sending out the right information :)

Posted in at 4:43 PM on Tuesday 13 February 2007 | Comments (4)
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On knowing extraterrestrials

Reading through one of the recent New Scientist issues last week I was amused by a line in a story about SETI and how the search for extraterrestrial intelligence must go on.

The story starts off with a comment that "[w]e live on a planet swamped by life forms yet we don't know how life got going, or where." Despite knowing so little of our own planet, the author later suggests that we know exactly the kind of signals that aliens will send to earth. He mentions the Allen Telescope Array that is "designed to pick up the kind of signal that an alien intelligence is most likely to send out into the universe: for example, a series of prime numbers transmitted in binary on a very narrow spectrum of radio frequencies."

I wonder, how exactly do we know what intelligent beings out there are going to be sending to us, if they do indeed exist, and want to send anything to their distant earthling neighbours?

Posted in at 9:59 PM on Monday 12 February 2007 | Comments (1)
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Google doodles in Hyde Park

I was in the Apple section of a department store in town yesterday having a test drive of the latest MacBook and MacBook Pro laptops when I noticed that they had Google Earth running on them. Trying the MacBook Pro out first, I was very impressed with the responsiveness of the machine when exploring in Google Earth. The MacBook wasn't quite as impressive, but still very nice and an improvement upon the iBook I've got at the moment.

Google Maps version of Hyde ParkAs I was exploring, I zoomed into London and specifically into the area of Hyde Park and its north eastern corner. I had spotted a road pattern that didn't look quite right on top of the imagery that was being shown. Hyde Park is full of criss-crossing paths that are really quite distinctive from above, but what I was seeing didn't fit that pattern at all.

It rather looks like a glaring intentional error has been introduced, perhaps so they can tell when people have copied their maps verbatim (read the Maps that Lye page on the OpenStreetMap wiki for more information).

Yahoo Maps version of Hyde ParkWondering if it was perhaps a series of paths that had been introduced after the aerial imagery had been taken, I took a look at Yahoo Maps to see what they showed and they didn't have the paths included.

I suppose the logic in adding erroneous data here is that it doesn't matter if you follow it as you're in open space anyway, and so it won't matter to pedestrians if the paths don't actually exist.

Posted in , at 6:55 PM on Sunday 11 February 2007 | Comments (3)
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Introduction to Neogeography

Have you ever been reading my blog and wondered what it is that I'm talking about, or why I'm so interested in everything geospatial (the vast majority of links I add to my del.icio.us bookmark collection use the term geo) and opensource software (especially in relation to the Drupal platform, which I got involved with through work)?

If you have, you may just find the Introduction to Neogeography by Andrew Turner a good primer. It's a great introduction (for those who already have a technological leaning) to the 'new geography', talking about concepts, common data formats, examples you can implement yourself and that sort of thing. It's a 54 page e-book and downloadable from the O'Reilly site.

The description reads

Neogeography combines the complex techniques of cartography and GIS and places them within reach of users and developers.

This Short Cut introduces you to the growing number of tools, frameworks,
and resources available that make it easy to create maps and share the
locations of your interests and history.

Learn what existing and emerging standards such as GeoRSS, KML, and Microformats mean; how to add dynamic maps and locations to your web site; how to pinpoint the locations of your online visitors; how to create genealogical maps and Google Earth
animations of your family's ancestry; or how to geotag and share your travel photographs.

I am glad that Andrew pointed out Drupal as a potential player in the GeoStack he talks about. As he puts it, "[t]he GeoStack encompasses the entire life cycle of geospatial data, from capture to consume using a variety of tools, formats, and applications." It's basically a suite of applications and services that can all speak geography to each other, sharing information with ease using standard formats. As an example, imagine going out with a GPS, uploading that information about your journey to somewhere, that site being able to share its information with sites that are designed to aggregate similar information and then have that available on demand, filtered as desired, to other services that can consume the information.

Drupal can actually play a part in each of these layers of the stack*, from allowing users to enter location information, serve it out, aggregate it from other sites and also be a consumer of that data.

* or will be able to again with a little work to get the newly updated location module and GeoRSS module talking properly with one another again

Posted in at 9:39 PM on Friday 9 February 2007 | Comments (0)
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5 things you didn't know about me

I was tagged by Nick Black a little while back as part of the 5 things you don't know about me meme that's been making its way around the internet. I've been putting it off, but here goes with five things that you may not already know about me:


  1. Let's start with a geographic one. The furthest east I've travelled is Cyprus (33.7 degrees longitude), furthest north is Anchorage (61.1 degrees latitude) and furthest west and south is Hawaii (21.3,-157.8).

  2. I have always instinctively resorted to using the Never Eat Shredded Wheat mnemonic whenever working out which way is east and which way is west.

  3. I have a condition that causes me to sneeze whenever I expose my eyes to the sun. (You may have read about sun sneezing already). It's generally two sneezes, and happens just moments after leaving a building. It's almost guaranteed that it'll happen, even if it's cloudy and there's only a slight hint of sunshine behind the greyness.

  4. I am perhaps the worst footballer ever, and always tried my hardest to avoid it (or anything similar) at school.

  5. On my way into work each day I pass the remains of a section from the Berlin Wall and also two tanks with their barrels pointing across the road.

And now to tag 5 people to do the same: Martin, Victor, Ivan, Adrian and Benjamin

Posted in at 11:52 PM on Thursday 1 February 2007 | Comments (1)
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