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A little while back, I posted a few mapping extensions that read in various kinds of data to allow mapping of regions and data on Google Maps. One major problem with those is that Google is now charging money for useof their mapping product, so in order to use this extension on any grand scale,they'd need to purchase licensing.
So, in response to this, I've built an extension which uses all open source (free) products to provide some similar mapping capabilities(and then some). The tool which provides the scrolling and "slippy" map features is called OpenLayers which reads in map imagery from OpenStreetMap. What I've done this time, however, is built the extension to read in KML files for the regions. KML is a format that is very common in the industry (Google Earth uses and creates the files) ,and there are many tools out there to convert other formats (like shape files) into the KML format.
So, for example, I went and found a KML file for the US 50 states and put it into this new extension, and was able to create a map similar to my other US Map extension:
New Features
Above and beyond the normal features of the extensions I created for Google, this extension provides a few new features:
- No more setting the zoom and center point - In the other extensions, you had to set the default center point of the map as well as how far in it should be zoomed when it loads. In order to make the map more user friendly and intuitive, this extension automatically determines the center point of all of the regions and sets the window to show the whole map. This way, also, if you click on a region, the map window will only show the selected region:
- Select Box -With this extension, if you hold down the shift key and drag an area with your mouse, a select box will appear, allowing you to select many regions at once:
Once the selection is made, the window will adjust itself to only show that region:
- Loading KML files - Loading KML files into the extension eliminates a lot of the manual work that was need for the other extensions. This way, as long as the KML names and QlikView dimension match up, KML files containing any kinds of regions can be used. So, for example, if a company has custom regions representing different sales regions, etc. in a KML file, it would be very easy to plug it into this extension.
- It's free- It uses open source technology so nobody will have to worry about licensing or being chased down by Google.
I've attached the extension as well as a QVW and quick guide. In the extension is a sample KML file called us_states.kml that can be used with the example QVW.
Please let me know if you have any questions. Hopefully this is useful to people.
UPDATE
Due to some issues with versions of Internet Explorer prior to 9 and how it handles different data formats, it is now necessary to change the KML file into an XML file prior to loading it into the extension. So, for example, if you have a KML named "counties.kml" you need to change the file extension so it becomes "counties.xml". Hopefully I'll eventually get time so this last step can be avoided, but for now it's necessary in order for the extension to work in IE8.
I've updated the attatchments on this post to use an XML file, so the examples should now work.
Brian (Great name, btw 
), i managed to make your extension work with UK Postcode areas, and to be honest, the most difficult part was sourcing a suitable KML file!
A suggestion as well: would it be possible to have a popup when mousing over an area on the map, that shows the region name and the relevant expression on there?
Great work, though. Very useful!
Hi,
I'm trying to get my map in the qvw but after trying all the steps mencioned above i only get the message:
Can someone help me?
Thanks in advance
Brilliant extension object Brian, I have managed to get a kml file of UK post code regions and have managed to get that working with it .. will post up soon - however it would have been nice to have a county KML .. it appears that these are really difficult to find and are potentially chargeable - if anyone finds one, can you drop it my way and i'll be happy to get it up and running in my Extension object and send the whole thing through ;0)
Sorry i didn't reply to you earlier, Julie. I should've shared my solution also, but you beat me to it. I've attached a screenshot.
I encountered similar issues to you in sourcing files for more granular levels of postcode detail, these only appear to be available by paying. And believe me, i know, because i spent quite some time trying to source them for free.
With regards to county KML files, i would say your best bet is downloading that from Ordinance Survey. You'll then have to convert the ESRI shapefile format it's supplied in into KML, which was the bit that just proved a step too far for me. There are tools out there to do it, but i encountered various issues such as the KML files generated being massive, or having to purchase full versions of the conversion software.
In the end, the solution regarding postcodes was dealt with pretty gracefully in IdevioMaps, which has built in integration for UK postcode sectors, districts and areas.