GIS opensource Thoughts

OpenStreetMap and Mainstream GIS start dating..

The image below tells us quite a lot about own the GI industry is developing.

OpenStreetmap data and ITN

Click on the image for a full resolution screen-shot of openstreetmap (OSM) data and OS ITN data in Cadcorp‘s SIS desktop GIS, which can now import OSM XML.

What do we have here…

1. Cadcorp a progressive but mainstream GIS vendor supporting open source data!
2. OK, it is Isle of Wight data, where OSM has particularly good coverage, but as one can see community generated open source data is comparable geometrically with “professional” Ordnance Survey data.
3. OSM data lacks the rich attribution of Ordnance Survey (e.g. classification A road, B road, Minor, path etc), which will restrict its use in many applications, but which will still meet the needs of many.

The story the image does not illustrate are the difficult problems of keeping the data current, and completing national coverage, areas which will be future challenges for OSM.

As I have blogged before the “Traditional” GI industry is only slowly beginning to wake up to the potential of community generated geodata, so full marks to Martin Daly and Cadcorp for recognising the potential.

One day very soon, community generated geodata will sit side by side with commercial professionally produced data for many GIS applications – as of today that day is a little closer.

Written and submitted from home, using my home 802.11 network.

6 replies on “OpenStreetMap and Mainstream GIS start dating..”

Hi Ed

On #3, OpenSteetMap actually has very comprehensive metadata and classification, it’s just not visualized in the Cadcorp plugin. The highlighted feature, “Post Office Way”, is classified as “highway=footway”.

The OSM map over the same area shows a bit more (and this rendering is still leaving out quite a bit of metadata).

OSM uses a simple Key-Value system to assign properties to Features. No enforced ontology, bottom up folksonomy .. but it is quickly converging on some standard practices, and still keeping flexibility.


HI Mikel,

The “traditional” GI market I don’t think is ready for a folksonomic approach yet – when do you think the key-value system will reach a level of maturity that all “B-Roads” will be classified as such.


SIS can of course render the OSM data in many, many ways. I left it like that purely for the purposes of comparing against the ITN. We can and have used the metadata for feature-based styling, and could apply this by default as we do with ITN. One for the next release, perhaps.

I agree with your last paragraph. Community based GIS is going to become prominent. The advantage it will always have is that the richness of attribution it will contain will always be relevent to the needs of that geographic area. Likewise, maintenance issues will be minimised, as the true benefit of the data will only be realised if it is maintained to the appropriate level of completness, accuracy and specification – but as the direct customer will be maintaining it, it will be self defeating to not let support eh data set. The only obstacle to Community based GIS datasets emerging is the current lack of shareware/freebie tools.

With the ‘Tools’ the data will be easily populated. Yes not as enriched as OS datasets, but with th likes of online/desktop editing starting to become more available with the likes of Google Earth (in beta 4), Udig, Mapserver and Google Maps. OSM will be able to complete the UK coverage. With good news that Yahoo! have allowed OSM to use its Aerial Imagery to capture road centrelines will aid the process.
Ed is correct and there is place for both a commerical products(ever more expensive) and an Open Source solution.
The work by OSM is a challenge but proving it can be done.

Google Maps Editor? why yes in Alpha but here


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