[GRASS-user] exporting raster map to kmz?

[Thomas Adams]

Sylvain,

I agree with your approach. However, I have run into one difficulty, which
is if the raster is very detailed (say, 1-ft Lidar) and the computational
region is relatively large (several square kilometers), GRASS has
considerable problems with the raster-to-vect conversion. The problem is
that each raster pixel is transformed to a polygon, so the result is that
there can be millions of polygons which the v.build process embedded within
r.to.vect , seems to run out of memory. This happens despite the fact that
I am running GRASS on 64-bit Ubuntu Linux with 16 GB RAM

My process is this:

r.to.vect -b input=flood_225.50 at teaiii output=flood_225_50 type=area

v.db.addcolumn map=flood_225_50 at teaiii columns="flood_area varchar(12)"
v.db.update map=flood_225_50 at teaiii layer=1 column=flood_area value=225_50
v.dissolve input=flood_225_50 at teaiii column=flood_area
output=flood_225_50_dissolve
v.out.ogr -c --overwrite input=flood_226_50_dissolve at teaiii
dsn=flood_226_50.kml format=KML

Over the same computational region, if my grid resolution is 3-meters, I
have no problems; with 1-ft (~0.3 meters) grid resolution, I have problems.

Regards,

Tom






On Fri, Jul 25, 2014 at 3:43 AM, Sylvain Maillard <
sylvain.maillard at gmail.com> wrote:

> Hi,
>
> kml is usually more used for vector data.
> looking at the header "<img style="margin-right: 0px;"
> src="data:image/png;base64,iVBORw0KGgo", it seems that r.out.gdal is just
> writing the binary code for your raster in an image tag in the kml file ...
>
> Have you try to transform your raster into vector (
> http://grass.osgeo.org/grass64/manuals/r.to.vect.html) and then to export
> the vector to kml ?
>
>
> Sylvain
>
>
>
> 2014-07-23 20:26 GMT+02:00 Vishal Mehta <vishalm1975 at gmail.com>:
>
>> Hi all,
>>
>> I'm trying to classify a LANDSAT8 image. In the process, i'd like to
>> export an unsupervised classification i did (using i.cluster, followed by
>> i.maxlik) raster (type:CELL) into kml/kmz, so that I could get some visual
>> idea of the classification. the classification is from 1 to 10, with null
>> data present.
>>
>> r.out.gdal -c input=lsat2014_unsupervised at PERMANENT
>> output=C:\Users\Vishal\Documents\GIS\file3.kmz format=KMLSUPEROVERLAY
>> type=Byte nodata=0
>>
>> but no matter what flags i try, i get a black box on google earth.
>>
>>
>> I'm just using the GUI options, Grass7svn on Windows. FYI, I do know how
>> to do this by modifying add-on r.out.kml in Linux, but it would be good if
>> i could just do my entire workflow on one platform.
>>
>> Thanks!
>> Vishal
>>
>> --
>> Vishal K. Mehta, PhD
>> Sr Scientist
>> Stockholm Environment Institute - US
>> 133 D St Suite F
>> Davis CA 95616
>> www.sei-us.org
>>
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>>
>
>
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