Re: Question about road display

• To: Jing Zhang <goldlion888@xxxxxxxxxxx>
• Subject: Re: Question about road display
• From: Bill Hibbard <billh@xxxxxxxxxxxxx>
• Date: Sun, 12 Jan 2003 20:36:30 -0600 (CST)

Hi Jing,

> I 've successfully created 3D terrain by using Visad. Now, I want to draw
> a road on 3D terrain. The road will be realized by drawing line between
> vector point.(Here, I'm going to use Gridded3DSet) But the vector point
> information that I readed from a special file(VMAP) only includes X and Y
> value, no Z value(elevation value). How can I draw the road up and down
> along with the 3D terrain.(Not just float on the 3D terrain) If I can get
> Z values from the 3D terrain according to X,Y values, I may can draw a
> road as what I thought. But I have no idea about how to retrive Z values
> from the 3D terrain.
> If you can give me any suggestion, I will be very thankful.

If you have an (x, y) value in a RealTuple, and your terrain
in a FlatField with MathType ((x, y) -> z), then you can get
the z value by passing the RealTuple to the evaluate(RealTuple)
method of the FlatField.

Good luck,
Bill

• References:
  • Question about road display
    • From: Jing Zhang