Re: ElevationGrid

[Vladimir Bulatov <bulatov@dots.physics.orst.edu>]

Neil Woodhouse wrote:
> 
.........
> 
> Sooo now for the questions.
> 
> If i read the spec right do i take it that the 0,0 co-ord is the top-left of the data set?. If this is the case then for British Ordnance survey maps the ElevationGrid ain't much use.
> 
> Does the same problem exist for the DEM. How is this got around.
> Contouring. How can this problem be tackled. Do i have to use the IndexLineSet, if so this means that i have to enter the main data set TWICE!!! and is VRML capable of contouring anyway. It's not mentioned at all!!.
> 
> Scale bars. Why doesn't VRML have a standard set of scale bars. Not all of us are interested in making imaginary worlds where scale doesn't matter.
> 
> So can anyone suggest or give some thought to a few additions or amendments to the ElevationGrid.
> 
> Eg. A ContourGrid spec.
>     A ScaleBar spec
> 
> Can we ( GeoVRML ) look into the different co-ordinate systems used by various countries and formulate some form of CoOrd spec.
> 
> All this, and i haven't even mentioned laying on the colour coding for the surface geology  LOD's etc, etc, ad naseum.
> 
> I await Napalm :-)
> 

HERE IT IS :-|

The problem with VRML is that it is complex enough to allow to represent
virtually everything, 
but browsers are buggy enough to make process of doing this very
difficult. This results 
in frequent requests of new nodes, which actually perfectly are
implementetable as 
as PROTOs with some scripting.

end of Napalm :)

Regarding the questions in this request: they came perfectly in time
when I started to 
make a set of visualization PROTOs in VRML and in particulary one
semifinished 
PROTO does solve some problems mentioned here. 
This is a PROTO for displaying two dimensional, two component data 
(elevation and some other property for example) defined on rectangular
regular grid.
Second data component is displayed as colour contours. Elevation (if
presented) 
is displayed as elevation. 

I use this PROTO for displaing map of electrical potential from several
charges. 
Charges may be moved by mouse and map is rediplayed immediatelly. It may
be funny to play with.

PROTO and everything is at 
http://www.physics.orst.edu/~bulatov/vrml/datavis/graph2iso_proto.wrl
 
Though the PROTO is very unfinished, comments are welcome anyway :)

All the best, 
    Vladimir 

PS. This PROTO is known to works only with Cosmo2.0. Does not work in
WV2.0.


-- 
Dr. V.Bulatov,  Physics Department, Oregon State University, 
301 Weniger Hall, Corvallis, OR,97331-6705, USA 
bulatov@dots.physics.orst.edu; http://www.physics.orst.edu/~bulatov/;
tel: 541-7371712