[Openstreetmap] Legal viability of using Landsat and SRTM data as basemaps

[Nick Whitelegg]

On Wednesday 20 Apr 2005 19:06, Andrew Birkett wrote:
> On Wed, 2005-04-20 at 13:39 +0200, Jeremy Stocks wrote:
> > I also have found the NASA SRTM site http://www2.jpl.nasa.gov/srtm/
> > interesting for its utilkity in developing contour maps.
>
> Yes, as I understand it, the SRTM and Landsat data are free of any
> copyright restrictions.  I am planning on using SRTM data for my
> streetmap of Edinburgh, to allow for a "cyclist's routefinder"
> application - ie. find a route from A to B avoiding hills!  I've yet to
> assess the data closely to see if need further filtering, but from some
> quick experiments it looks pretty good (at least at the level of detail
> which is relevant for cyclists).

I use SRTM data on my Freemap site: http://www.free-map.org.uk. The contours 
seem to be pretty accurate to me in terms of correct horizontal positioning 
of hills and valleys. From a vertical point of view, they get confused by 
tree cover so tree-covered hills are perhaps 20-50ft higher than they should 
be.

The SRTM data is, I believe, public domain data. For a demo visit the Freemap 
site: contours for the whole of the UK below 55N are present.  You can also 
download the source code (PHP) of the site, including the contour generation 
routine, at http://www.free-map.org.uk/downloads.php. The code is under LGPL. 
The source code tarball is a month or two out of date (includes contours but 
no height shading which is on the current version of the website) but I hope 
to upload a more recent source code tarball very soon.

Nick