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Brian_Munz
Employee
Employee

Open Source Geospatial Mapping Extension using KML files

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:

map_shot.png

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:
    one_state.png
  • 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:
    select_box.png
    Once the selection is made, the window will adjust itself to only show that region:chosen.png
  • 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.

176 Replies
Not applicable

Hi Arun

thank you for the answer. It's so simple but (because there is alaways one), what files are needed to  build the .qar?

I saw Definition.xml. What informations are needed to script it?

Do I have to know Java script?

So, is there any tutorial which show how to build a .qar for maps?

Best regards

Chris

Not applicable

Hi Brian,

Could you please share the us_states.xml file.

I want  to create it for other states.

I am trying for all the countries and states inside it.

Thanks in advance,

Keerthi

Not applicable

Hi Arun,

Can u tell me how its done for india???

Thanks in advance

Keerthi

Not applicable

Hi,

Minimum 1 file (Defination.xml) is required to build an extension object.

To enhance it, we can add property and script file.

You can follow this tutorial for building a basic extension object. Can convert it to .qar file to directly install it in QV.

http://www.qliktips.com/2011/01/beginners-guide-to-qlikview-extension.html

Not applicable

Hi,

You have to develop a KML file for that.

Just find open data for indian states, and prepare kml file to use in extension.

Not applicable

can u share your kml files.

Not applicable

Hi Brian,

Cau you share the KML files. I want KML files for some countries.

Thanks in advance,

Keerthi

Not applicable

Hi Brian,

Could you please share the KML files you have.

I have for US States. Need other countries too.

Thanks in advance,

Keerthi

Brian_Munz
Employee
Employee
Author

I don't really have a library of KML files, but they're not that difficult to find online.  Natural Earth is a good resource:

http://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/

Brian_Munz
Employee
Employee
Author

FYI everyone I've combined this map (which doesn't work in IE 10) with my DRAFT map on qlik market and fixed the IE problem. See this post for more info New map that reads KML files and plots coordinates