Coverage from a Vector {Plow,Plough,Spray,Search}ing

[Eric G . Miller]

On Tue, May 30, 2000 at 11:16:49AM +1000, James Cameron wrote:
> I've got a vector track for a vehicle.  How do I convert it into a
> raster of coverage assuming a given perpendicular spread?
> 
> I know that s.to.rast can be used to create a raster where each site
> is expanded into multiple cells.  But that is only useful if one assumes
> a circular(?) coverage at each point.

What about v.to.rast? That is, you have a vector line (don't build
areas!), you convert it to a raster with v.to.rast and then you make the
raster grow to match the application spread.

> Also, in the case of chemical application, the rate of application
> depends on the speed of the vehicle ... and even the rotation caused
> by turning.

Hmm, more difficult. I see where the application would be greater on the
inside of a curve than the outside, and would be dependent on the angle
of the curve (overlap). Perhaps this is a job for mapcalc? Is the vector
track over regular units in time, or is it continuous with a speed
element?  

> Are there programs in GRASS that handle this?

I don't know, think you'll need to roll your own.  Perhaps by using a
series of additive matrix filters on the original points.  I suppose
they'd have to be applied in order of the track so that the direction of
the vehicle can be accounted for.  Sorry, for the non-answer.
Interesting problem ;) Please post the solution when you find it.


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