I have decided to move on from hosting on wordpress.com, so my RSS feed has changed to http://blog.timwarr.net/?feed=rss2 Please update the feed you consume.
The blog blog itself remains on blog.timwarr.net (minus the redirect to wordpress.com).
GIS and Web Mapping news and tips
I have decided to move on from hosting on wordpress.com, so my RSS feed has changed to http://blog.timwarr.net/?feed=rss2 Please update the feed you consume.
The blog blog itself remains on blog.timwarr.net (minus the redirect to wordpress.com).
var locations = new Array(); var xy1 = new MMPoint(523000,212324); // OSTN97 OS National Grid var xy2 = new MMPoint(323000,212324); var xy3 = new MMPoint(423000,212324); locations.push(xy1); locations.push(xy2); locations.push(xy3); var funcRef = convertResultsLoaded; var converter = new MMConverter( funcRef ); converter.convert(locations, 'osng'); function convertResultsLoaded() { console.log(converter.result_set); };
A while ago I blogged about using OS Grid References in the Multimap API. Web mapping developers in the UK often grew up with Ordnance Survey (OS) maps, are used to using the associated OS grid references (rather than lat/lon) to specifiy location and want to use them in mapping APIs.
Previously Multimap released a new feature in the API to allow developers to convert grid references to lat/lon for use in the API. Multimap have a fantastic technical writing team and they have just released documentation on this feature (which is called Coordinate Transformation).
The documentation on how to use the features in the Multimap JavaScript API is here and the documentation on how to use the features with the Multimap Web Services is here.
Thanks to Manu Gaur for this great documentation.
Happy coordinate transforming!

Today (1st December) is world AIDS day.
The AidsInAfrica.net site has an interesting animated map here which shows an interesting time animation of the increase in HIV infections. It is sobering stuff and a nice example of the power of simple maps.
At last the Location Strategy for the UK has been published here. It was started in 2005. I have not waded through it all yet….
An initial skim suggests the main recommendation is more integration of public sector data through common references (DNF is mentioned). There do not seem to be any radical “Free our data” type statements, but they do say dataset owners should:
…simplify their licensing
arrangements so as to facilitate the sharing
of data to realise greater overall value
Oh, and we would get a new government “Location Council” to deliver the new Location Strategy.
I have been taking some time to explore there latest spatial thinking and innovations by Yahoo!. Setting aside some of the current business politics, I think Yahoo! are doing some of the most interesting stuff at the moment.
It started a while ago with their Where On Earth (WOE) IDs. Basically these provide a hierarchical identifier system based on location. I must admit it took me ages to realise what these are all about. I have a map centric view centric view of the world and places, so it seemed very odd at first. WOE IDS geo-tag (i.e. locate) things in a very different way (with no need for a map or lat/lon). When talking about a place all people really care about is what place it is and how to ensure that they are all talking about the same place (even if you might individually define its extent differently). Lets take an example, if we want to share data relating to Soho, how do we make sure we are talking about the same place? So with this system we do not have to argue endlessly about what the lat/lon of Soho is (or even worse try and define it’s extent), all we have to agree on is that Soho is in London which is in England which is in Great Britain, give it an ID and then we know we are talking about the same place…
So what I love about WOE ID is it is a simple non mapping solution to an age old spatial problem. In fact a map is ultimately relegated to just a display function.
So ahy has this now got really interesting? Well Flickr has been storing WOE IDs for geo-tagged photos. From this Yahoo! have been able to predict the extent of places (with WOE IDs) based on the geo-tags for the relevant Flickr photos. The resulting geometries are know as Alpha Shapes. So this is a completely different way to discover more about the geo-extent of a place. Taking the Soho example (which BTW is not an officially defined area) we can define it’s extent by what most people (taking photos) think it is. There are examples and details of this approach here on the Flickr development blog..
What I love about this is that, by taking a non map-centric view of place, Yahoo have developed an approach that can tell us more about what the the perceived geographic extent of a place is. No GIS person would ever think of doing it this way round!
Even better you can get the data yourself (as ESRI shapefiles) and try the software Yahoo use to create the Alpha Shapes (called Clustr).
More details on Alpha Shapes are blogged here too.
Lets hope this innovation continues!
I was chatting to John McKerrell yesterday and he was showing me his new creation http://mapof.it/. This is one of the coolest thinks I have seen recently and like all really cool things it is really simple.
Basically http://mapof.it/ allows you to build URLs that take you to a specific location (or route) on a web mapping site of your choice. So http://mapof.it/innsbruck will take you to a map of Innsbruck. You can also request a route between two places like this http://mapof.it/munich/innsbruck. In a way it is a kind of understandable TinyURL for maps! You can specify a mapping site of you choice using this approach: http://mapof.it/mm/graz,austria or set a specific site as your default with http://mapof.it/set/mm (this preference is saved as a cookie).
What I love about this is it is simple, useful (as an easy way to send a link to a map of have an easy URL to type) and you can choose which mapping provider you want to use.
More info is on John’s blog.
So only one question remains: How many spelling mistakes will John find in this post?

Martin Daly has done a review of embedded map tools and Multimap comes out top. More details on how to use this are here.