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

[Thomas Adams]

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>
wrote:

> Hi Thomas,
>
>
> On Mon, Jun 16, 2014 at 1:47 PM, Thomas Adams <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
>
> 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)
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