[Talk-ca] height data

[Richard Weait]

On Fri, May 27, 2011 at 2:22 PM, john whelan <jwhelan0112 at gmail.com> wrote:
> There seems to be considerable interest in flooding recently.  The UK
> has a government site
> http://maps.environment-agency.gov.uk/wiyby/wiybyController?ep=maptopics&lang=_e
> that shows the risk of flooding for a particular area.
>
> How would you obtain / insert height data into OSM?

You don't.  ;-)

Height data is more difficult to acquire accurately.  Our
consumer-grade GPSr devices are much better at lat and lon than
elevation.  With no good way to acquire, and update elevation data, we
as a community have decided to leave it out of the OSM data base.
There are exceptions to this and there are adaptations to this,
namely:

POI heights.  There are occasional heights for point objects like
mountain peaks, and communication antennas.  They aren't widely used
but you can see some of these in the data.  We don't see elevation
data for every peak or for every communication tower or building.

Elevation mash-ups. OpenCycleMap combines OSM vector data with SRTM
raster elevation data.  The combined information is presented for
cyclists, with hill-shading and contour lines.  Many other renderings
have used similar methods to combine elevation sources with OSM data.