UKTC Archive

Re: OS OpenData

Subject: Re: OS OpenData
From: Chris Hastie
Date: Jan 02 2015 10:58:04
On 31/12/14 18:58, KEVIN SURRIDGE-DINES wrote:
Does anyone have any experience using the (freely?) available OS
OpenData maps? If so how have used them, what are/aren't they good
for?

That's a huge and complicated question Kevin. Perhaps you could be more
specific about what you're thinking of doing? Also, I notice you say
"OpenData maps", rather than just "OpenData". Have you a specific type
of map created from the open data in mind? Or was the distinction not
intentional?

I've never used maps built by other from OS OpenData, but I have used OS
OpenData. The postcode search for tree surgeons at
http://www.tree-care.info/findanarb and the associated map at
http://www.tree-care.info/maps/ both make use of Code-point Open, part
of the OpenData suite, to geocode postcodes.

But beyond Code-point Open my use has been limited. I don't generally
find the OS OpenData offers me anything that OpenStreetMap data doesn't,
but OSM does often offer me more detail that the OSOD. Round here
someone's even plotted half the street trees! There's a lot missing from
OSOD—you'll find no footpaths in there for example. So I tend to use OSM
data. OSM aslo tends to get updated faster when things change, and if it
doesn't, you can do it yourself. Obviously this last point is perhaps
also the one big advantage of OSOD over OSM—it's more definitive. OSM's
'crowd-sourced' nature does make it vulnerable to malicious changes in
much the same way as Wikipedia.

I do make use of the OSOD Boundary-Line data set, or of derived data
sets (often supplied by the Office of National Statistics). They're
easier to use for most purposes than the boundary data in OSM. And I've
played with OS Terrain 50. But the fact that it comes in 10km square
tiles makes it a bit of pain to work with across large areas. So if I
need contours I tend to go for the NASA SRTM data.

Most of my uses these days are for strategic analysis at large area
level, for which OSM + Boundary-Line works well. If you need to generate
base maps for site surveys I would suggest that neither OSM nor OSOD is
going to do. You're going to have to spend money on OS Master Map.

All of these comments are based on using *data*, rather than maps, in a
GIS. If you're not used to GIS, and all you need is maps, then there is
a steep learning curve involved. And a lot of initial fiddling to style
the data to display properly. OS do make available some style sheets for
ArcView I believe, but I've never got them to work well in my preferred
system, QGIS.

HTH

Chris




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