Hello Phil, >> Am interested in using the OS OpenData contour set for an >> augmented reality app for walkers (extension of the OpenTrailView >> idea). What I have in mind is to load them into a database >> and implement a lookup facility where the elevation at a >> particular lat/lon can be obtained by querying the dataset. >> I believe the OS contours are rather higher precision than >> SRTM, hence my interest in them, but to potentially save >> effort, has anyone done something like this already?
>I believe you've asked me about this before, and I have code to parse >the gridded version of this data and to create binary files from it, >similar to the ".hgt" files that SRTM is distributed in. The total >size is about 60 MB in about 13,000 gzipped files, one per 5km square, >with a 50m horizontal resolution. Trivial interpolation within the >grid seems to work pretty well compared to OS spot heights e.g. within >5m on summits, which is much better than I get using SRTM. I also have >a version that is downsampled to a 200m grid which is of course much >smaller. Lookups are quite straightforward once you have converted >your lat/lon to eastings and northings. >You are welcome to take a copy of this data, if you would like it. Yes, could be useful, thanks. Sorry - what I thought I asked about last time was about VectorMap District data. No great urgency - just thought I'd raise it now as the OpenDEM post on the talk list reminded me about it. Nick
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