[GRASS-dev] Re: [GRASS-user] how to measure distances in a constrained space

[Moritz Lennert]

On 13/11/08 10:04, Hamish wrote:
>> r.grow.distance creates a distance map from each point, but
>> there is no way of telling it anything about null cells or
>> barriers. Even when setting a mask, r.grow.distance fills in
>> the whole region, which seems like a bug to me.
> 
> 
> perhaps if you invert the map?
> 
> 
> ie put starting point in null space and it will grow until/around cells
> with value?

You mean invert the mask, so that land masses are nulls and water 
non-nulls ?

Doesn't work.

r.grow.distance just seems to ignore the mask. Glynn ?

Moritz