[OSM-dev] SRTM relief

[Nick Whitelegg]

On Thursday 03 Jan 2008 08:53, you wrote:
> On Jan 2, 2008 11:50 PM, Nick Whitelegg <nick at hogweed.org> wrote:
> > Hello Andy,
> >
> > There is the srtm2shp utility available in SVN which outputs a shapefile
> > of contours, it outputs in Mercator - is that any good? It doesn't deal
> > with SRTM voids yet.
>
> I had seen that when you posted about it recently. I haven't tried it
> out yet, but I have more confidence in the usefulness of your scripts
> than of mine, but I couldn't get the older version of your scripts to
> work for me.
>
> One of the things I haven't worked out yet is how to render
> planet-wide contours in an efficient manner, since the shapefiles
> mulitply either in size or number to rather large amounts (for 10m
> contours especially) as I start including europe, never mind in the
> US. I found there were more than 4GB of contours for the UK, which
> made it impossible to combine the results for each SRTM->shp
> conversion into one large shp file.
>
> Cheers,
> Andy

The srtm2shp actually generates one big shapefile, it does it by tiles (by 
default 0.1 x 0.1 latlon or 10000x10000 mercator units) and then merges each 
shapefile together. It takes a fair while to do the whole of the UK (a few 
hours IIRC) but the resulting shapefile, when indexed using Artem's 
shapeindex utility, is manageable to use - I currently use one big UK 
shapefile on Freemap, it's a little on the slow side in mountainous areas 
(i.e. Lake District, Snowdonia, Scottish Highlands) but not too bad.

Nick