Open Data and Spatial Formats

[Huw Davies]

Hi All,

I've been doing a bit of work with the Open Data team trying to get
some of our (and Ordnance Surveys) spatial data into a usable format
for the Open Data Site.

I've gone with KML initially as this is an OCG standard for spatial
data and I know it can easily be used with both Google Earth and
Google Maps, however some of the files have been coming out quite
large - and potentially could be unwieldy and slow to load, so I was
just wondering whether anyone has tried to pull in any of the KML
files I've put out there and how they found them to use?

We could potentially provide files that have been generalised (i.e.
points removed) - this would make them faster but potentially less
accurate.

We also have the ability to provide a range of different file types
including SHP, GML, TAB and many other others if people would find
these more useful, as well as different coordinate projections
including OSGB (we chose WGS84 as a standard for the Open Data project
because that's the format that the commonly available internet mapping
services use.

We could also potentially use Web Mapping Services like WMS or WFS if
this was considered worthwhile.

Any views on this will be gratefully received!

Huw Davies
GIS Manager, Warwickshire County Council

[Stuart Harrison]

Hi Huw,

I think for big files that aren't regularly updated, SHP is a pretty standard solution, and (with a bit of fiddling) it's perfectly possible to get them into 'web friendly' formats. OS have a lot of their open data in this format and no one's complained so far! I'd definitely stick with WGS84 as a coordinate system though, as 99% of people who do stuff on the web will be using this format.

Hope this helps

Cheers

Stuart

P.S. Out of interest, what GIS system are you using? In my day job at Lichfield, the GIS officer and I are having a few problems pulling stuff out of ArcGIS server in WGS84 without there being massive discrepancies. If you can give us some pointers off-list I'd be eternally grateful!

[Huw Davies]

Thanks Stuart, that's useful to know - we'll offer files as both SHP
and KML in WGS84 for now then and see how that goes....

I'll drop you an e-mail on t'other bit.....

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