[GRASS-user] Question about v.to.rast

[Thomas Adams]

Apologies, I wrote v.to.rast in my subject when I meant r.to.vect -- not
sure how I did that!

Tom

On Monday, June 16, 2014, Thomas Adams <tea3rd at gmail.com> wrote:

> Margherita,
>
> Thank you for the suggestion; yes, the raster pixels are at the resolution
> of the raster map, so the r.to.vect conversion is creating vector polygons
> of the size of the individual raster pixels. If I can aggregate all of the
> raster pixels using r.area, then that should do what I want, I think.
>
> Cheers!
> Tom
>
>
> On Mon, Jun 16, 2014 at 7:55 AM, Margherita Di Leo <diregola at gmail.com
> <javascript:_e(%7B%7D,'cvml','diregola at gmail.com');>> wrote:
>
>> Hi Thomas,
>>
>>
>> On Mon, Jun 16, 2014 at 1:47 PM, Thomas Adams <tea3rd at gmail.com
>> <javascript:_e(%7B%7D,'cvml','tea3rd at gmail.com');>> wrote:
>>
>>> All:
>>>
>>> I have used r.lake to simulate flood inundation in an urban area -- the
>>> raster looks great! What I want to do (and have done) is to use r.to.vect,
>>> export the vector as a KML (which works), bring the simulated flood
>>> inundation map KMLs into GoogleEarth and create some animations from the
>>> simulated inundation, including showing rising flood levels inundating the
>>> city streets in 3D.
>>>
>>> I can basically do all this, except that the r.to.vect conversion
>>> creates a gazillion boxes that are the size of the raster pixels -- I don't
>>> want all the tiny boxes.
>>>
>>
>> I'm not sure I understand correctly, but if the tiny pixels are there
>> also in the raster map, might be useful r.area (addon) [1].
>> Hope this helps,
>>
>> Cheers,
>> madi
>>
>>
>>> What I want, is just a single (albeit, complex) polygon showing the
>>> flooded areas. v.dissolve will remove the boundaries of adjacent boxes if
>>> their cat or attributes are the same -- is this the way to go, namely, make
>>> all the cats or attribute values the same and then use v.dissolve?
>>>
>>> Or, is there is there a better way to do what I'm attempting to do? That
>>> is, is it best to keep the individual small vector boxes for reasons I'm
>>> not considering?
>>>
>>> Thank you,
>>> Tom
>>>
>>>
>>> [1] http://grass.osgeo.org/grass70/manuals/addons/r.area.html
>>
>>
>>
>> --
>> Best regards,
>>
>> Dr. Margherita DI LEO
>> Scientific / technical project officer
>>
>> European Commission - DG JRC
>> Institute for Environment and Sustainability (IES)
>> Via Fermi, 2749
>> I-21027 Ispra (VA) - Italy - TP 261
>>
>> Tel. +39 0332 78 3600
>> margherita.di-leo at jrc.ec.europa.eu
>> <javascript:_e(%7B%7D,'cvml','margherita.di-leo at jrc.ec.europa.eu');>
>>
>> Disclaimer: The views expressed are purely those of the writer and may
>> not in any circumstance be regarded as stating an official position of the
>> European Commission.
>>
>
>
>
> --
> Thomas E Adams, III
> 718 McBurney Drive
> Lebanon, OH 45036
>
> 1 (513) 739-9512 (cell)
>
>

-- 
Thomas E Adams, III
718 McBurney Drive
Lebanon, OH 45036

1 (513) 739-9512 (cell)
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