Sunday, 15 October 2017

All the UKs frequencies on Google Earth?

Yesterday, someone pointed out to me that it was possible to download the whole of Ofcoms license allocation database, as a comma separated variable delimited file. This is the list of who holds what licenses for what specific frequencies, not amateur licenses, or users of license free channels.

This info of course is of great interest to scanner users, but the original .csv file rocks up at over 70MB and around a third of a million entries!

Now, wouldnt such a file, showing who is using what frequencies and where, be great on Google Earth?

Glutton for punishment that I am, and recognized at work as the Google Earth Gnome, I foolishly set about trying to convert a 70MB .csv file into a workable set of .kmz files!

Key to this, are three steps - First, remove all non-geographical entries. These are frequencies and users allocated on a nationwide basis, and hence have no position information for Google Earth to work with. Second, remove all duplicates. In this case, a duplicate entry is one where the same user, is listed with the same frequency, in the same location. A frequency can be used by the same user in a different location, thats a valid entry, as is a different user using the same frequency, etc. And third, split the file into manageable chunks.

The first two operations have been done using the data handling tools in Microsoft Excel. The third needed some thinking about. I opted to split the file into separate files based on area, and chose to use the Ordnance Survey 100km gridsquares


Most areas, this creates an easily handled file size. The exception is grid TQ, which covers that there London. The density of allocations in London is such that I have had to split that file into four, and perhaps even more, based on frequency band.

The resulting .csv files, can be imported direct into Google Earth. Ultimately, I wish to convert them to .kmz files that are native to Google Earth and can be distributed, such that any user can just open the file and it will work. Imported .csv files require some setting up.


The above pic is a screenshot of my Google Earth Pro with three of the gridsquare files imported and enabled.

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