[GRASS-user] v.to.rast gives empty raster layer

[Micha Silver]

On 05/03/2011 04:34 PM, Moritz Lennert wrote:

> On 03/05/11 10:20, Micha Silver wrote:
>> On 05/03/2011 09:11 AM, Hanlie Pretorius wrote:
>>
>>> Hi Maris,
>>>
>>> Thanks, your suggestion worked. With the region's resolution set to
>>> 5m, I got some output.
>>>
>>
>> Hi Maris:
>> Sorry for butting in on this, but I don't understand why the region
>> resolution should make any difference to v.to.rast??
>> Would you mind to explain?
>
> From the v.to.rast manual:
>
> "v.to.rast will only affect data in areas lying inside the boundaries 
> of the current geographic region. Before running v.to.rast, the user 
> should therefore ensure that the current geographic region is 
> correctly set and that the region resolution is at the desired level."
>


Thanks, Moritz
What I'm trying to understand is the question about resolution. Would 
you expect, as
Hanlie indicted, to get *no output* in the raster because of too course 
resolution?
He claims that at 20m x 20m v.to.rast of a line feature created all NULL 
cells, but at 5m x 5m the lines did appear in the raster.
??

> And, more generally, from the Raster data processing intro page:
>
> "As a general rule in GRASS:
>
>    1. Raster output maps have their bounds and resolution equal to 
> those of the current computational region."
>
> Moritz
>
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>
>


-- 
Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il