[GRASS-user] Error using v.rast.stats script in cigwin and wingrass

maning sambale emmanuel.sambale at gmail.com
Tue May 20 22:33:47 EDT 2008


Hi,

Using v.rast.stats in grass6.3 both in cygwin and native windows,

v.rast.stats vector=myupland_lowland at allah_valley layer=1
raster=allah_dem at allah_valley colprefix=dem percentile=90

I get this error

:/GRASS/scripts/v.rast.stats: r.cats: command not found

I see no entry in the 6.3 manual on r.cats

any ideas on using v.rast.stats?

On Wed, May 21, 2008 at 2:44 AM, Jonathan Greenberg
<greenberg at ucdavis.edu> wrote:
> Juan:
>
> Some responses below:
>>
>> Well, that's exactly the problem, i cannot make a complete mosaic for the
>> region i'm working on with only images taken on one day, and it adds
>> another
>> problem: the images do not overlay well... if they did, i would been able
>> to
>> do a radiometric normalization easily (as Johnattan Greenberg
>> suggested)...
>>
>>
>
> By "do not overlay well" I assume you mean they aren't well orthorectified
> to one another -- although I consider this a "must do" for mosaicking and
> for any level of image-to-image work (because of the time savings), you
> COULD manually pick PIFs in the overlap zone (e.g. you'd pick a point in the
> reference image, then visually pick the corresponding pixel in the
> uncorrected image) -- orthorectifying first saves you the time of having to
> pick two points per image -- rather, you just pick one point.  How many
> images do you have in your mosaic?  Image-to-image rectification with
> landsat imagery is fairly painless, shouldn't take you much more than 30
> mins per image once you get going with it.
> At any rate, once you pick your PIFs, you can use v.what.rast or starspan
> (starspan.casil.ucdavis.edu) to get this data out to a table to do the
> regression calculations.
>>
>> So my problem now is how to overlay landsat images taken in different
>> days.
>> I've already asked for help on this issue (with no solution so far; mail
>> subject="mosaic with landsat geotiff"), so guess i'll resume that
>> thread...
>>
>>
>
>
>>> if it is simply an "automatic contrast" adjustment, you could linearly
>>> interpolate between bands so they matched. (but then which is correct?) I
>>> don't think it would be though, as LANDSAT has fixed calibration for each
>>> band.
>>>
>>
>> How's that?
>>
>>
>
> This is what I suggested as well -- the question of which one is "correct"
> is somewhat moot -- your goal, as I understand it, is to have all of the
> images in the same radiometric scale, so you can just pick one (usually one
> that's in the middle of your mosaic, and often temporally at the "edge" of
> your time period (either a very early or a very recent image).  If
>>>
>>> if you run i.landsat.rgb on the two images with the same parameters do
>>> they
>>> match up well?
>>>
>>
>> what do you mean with 'the same parameters'? (maybe "cropping
>> intensity"...)
>>
>>
>>>
>>> that doesn't touch the values, only the colors, but it may
>>> give you a clue about the cause of the difference.
>>>
>>
>> How exactly? as an example, i can see a subtle difference in the color of
>> water in a river as it pases on to another 'tile', but what does it means,
>> i
>> don't have a clue... (the values changes from: |32|40|86| to |20|26|69|,
>> for
>> bands 3, 2, 1 respectively)
>>
>>
>>>
>>> I guess the important thing is the ratio of the bands, not the exact
>>> values
>>>  of one particular band. I take it you see a hard line at the boundary in
>>> the processed image?
>>>
>>
>> i suspect you mean the same as Johnattan G. with the radiometric
>> normalization... anyway, i don't know what you mean with 'proccesed
>> image'.
>> The original images come with a null region as a result of the
>> georreferencing, and after i use r.null -r to remove the NULL-value bitmap
>> file, yes, there is a hard line in the boundary, but what would that mean?
>>
>>
>>
>
> It just means your images aren't radiometrically normalized to one another.
>  If you correctly normalize them you won't see a line in the mosaic.
>>>
>>> Hamish
>>>
>>
>> JM
>> -------------------------------------------------------
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>> grass-user at lists.osgeo.org
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>>
>>
>
> --
> Jonathan A. Greenberg, PhD
> Postdoctoral Scholar
> Center for Spatial Technologies and Remote Sensing (CSTARS)
> University of California, Davis
> One Shields Avenue
> The Barn, Room 250N
> Davis, CA 95616
> Cell: 415-794-5043
> AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307
>
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>



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