SRTM is raw height data at approx 90m intervals which is perfect for this sort of visualisation
work. It does require a bit of processing so that it is useful i.e. converting into the map's
projection, interpolating for any voids and enriching with known spot heights from your own
waypoints.
OS 1:25,000 maps usually provide enough detail as does the aerial photograph, 1:50,000 are a little
sparse but this can be overcome by alpha blending a tileable ground detail texture into the map
image. I've provided 3 preset 'realistic' textures taken from landscape photographs that can be
blended into to give a semi-realistic end result. It's definately the case that aerial photographs
give the best results though.
You do need a reasonble PC and graphics card to get a fast response, my home PC with 900MHz CPU and
a basic 2MB Intel motherboard graphics card is just about acceptable but certainly not fast. My work
PC is a 2Ghz cpu with an 8MB NVidea GeForce card and that gives excellent results.
"Dave Moore" <[email hidden]> wrote in message
"]news:[email hidden]...
Quoted message said:When you say that the data is freely available from NASA, is that the
height
Quoted message said:(or DTED) data?. Presumably to generate a view like that, you'd need ariel or satellite photograph
also?. Having done a bit of OpenGL programming myself previously, I had a play at overlaying OS
maps on 3D terrain which did look pretty good especially with lighting switched on, although the
amount of texture data required for good map definition was considerable, but not unreasonable
given the memory and hardware acceleration
capabilities
Quoted message said:of the games graphics cards now available.
Dave
"Andrew W" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:I thought the 3d view in MM was a bit limited considering the
possibilities.
Quoted message said:I'm working on the next release of Trailgauge into which I've incorporporated a 3d game engine
to render terrains in realtime. This
allows
Quoted message said:you to position yourself in the 3d landscape and move about on the
surface
Quoted message said:Quoted message said:(or at a fixed altitude above it) rather like games such as Doom etc.
This
Quoted message said:Quoted message said:means that you get to see the same views as you would in real life and
means
Quoted message said:that you can thoroughly explore an area before even setting foot in it.
Here's an example: trailgauge.co.ukgoyt.wmvOpen ↗
The quality suffered when recording the movie so isn't that
representative
Quoted message said:Quoted message said:of what you see on the screen, also the speed is a bit slower than
normal
Quoted message said:Quoted message said:but it gives you an idea. The data is the freely available SRTM data
(from
Quoted message said:Quoted message said:NASA) - Trailgauge does any conversions and cleaning required on the
fly.
Quoted message said:Quoted message said:
I'm hoping to have it completed and ready for release by the end of
January
Quoted message said:and I'm also hoping that I can reach some agreement with third parties
to
Quoted message said:Quoted message said:allow access to UK raster map data for a reasonable cost. I'll keep you posted.
"sandy saunders" <[email hidden]> wrote in message news:N9iIb.13179$526.88806@newsfep4-
glfd.server.ntli.net...
Quoted message said:> Has anyone got the 'demo version' downloadable from the web to successfully display 3D
> images?. When I try I just get a message
saying
Quoted message said:Quoted message said:that
> 'this computer is not able to display the 3D image (Error: 314)' and
then
Quoted message said:> goes on to say that I need to install directX. Installing directX
doesn't
Quoted message said:> make the slightest difference!!. The 2D stuff works fine. The 3D images of Wasdale in the
> recent walking mags look pretty
impressive.
Yes, downloaded it a couple of weeks ago and it works OK. Quite
interesting
Quoted message said:seeing a 3D version of the map.
--
Sandy Saunders @ www.thewalkzone.co.uk
'Mountains or Mole Hills ... summiting still brings the same excitement'