[GRASSLIST:6887] Re: beginner's question

[Rahul Chopra]

Thanks Moritz. It now appears embarassingly obvious.

----- Original Message ----- 
From: "Moritz Lennert" <mlennert at club.worldonline.be>
To: "Rahul Chopra" <rchopra at uchicago.edu>
Cc: "Ian W. Macmillan" <ian_macmillan at umail.ucsb.edu>; "GRASS Users list" 
<grasslist at baylor.edu>
Sent: Wednesday, May 25, 2005 3:21 PM
Subject: Re: [GRASSLIST:6885] Re: beginner's question


> On Wed, May 25, 2005 21:29, Rahul Chopra said:
>> Thanks for your reply Ian. I actually figured out the script for multiple
>> imports of raster files. It goes a little like this
>>
>> for file in *.tif
>> do
>> r.in.gdal in=$file out=$file
>> done
>>
>> As for the UTM lat-long conversion, since the data is in UTM coordinates,
>> I'd like to create my grass location in it too and thus the struggle for
>> converting lat long to UTM. What gdal command do you use?
>
> Why do you need to convert from lat-long ?
>
> You have two choices:
>
> 1) if you know your datum settings (projection and ellipsoid) than you 
> create
> a new location with these settings and directly import your data there
>
> 2) if you don't know your datum settings, than in any existing location
> (whatever its datum), run r.in.gdal with the location= option for one 
> raster
> to have it create a new location with the appropriate settings. Then you 
> can
> run your above script with the '-e' flag for gdal to extend the location 
> as
> needed for the different raster files.
>
>
> Moritz
>
>
>>
>> Rahul
>>
>> ----- Original Message -----
>> From: "Ian W. Macmillan" <ian_macmillan at umail.ucsb.edu>
>> To: "Rahul Chopra" <rchopra at uchicago.edu>
>> Cc: "GRASS Users list" <grasslist at baylor.edu>
>> Sent: Wednesday, May 25, 2005 2:13 PM
>> Subject: Re: [GRASSLIST:6882] beginner's question
>>
>>
>>> Rahul,
>>> Short answers follow, but hopefully they might point you in the right
>>> direction.
>>>
>>>
>>> Quoting Rahul Chopra <rchopra at uchicago.edu>:
>>>> Hello all,
>>>>
>>>> Am new to the mailing list and have a couple of novice like questions.
>>>>
>>>> 1. I have downloaded several Landsat ETM+ files which I wish to import
>>>> into
>>>> my GRASS location using r.in.gdal. Could someone provide some help with
>>>> what
>>>> the script might have to look like in order to import multiple tif 
>>>> files
>>>> into this location?
>>> SORRY NO HELP FOR YOU HERE.  I JUST USUALLY RUN R.IN.GDAL MULTIPLE TIMES
>>>
>>>
>>>> 2. In order to apply radiometric corrections I ran grep BIAS 
>>>> dataset.met
>>>> and
>>>> get the message CORRECTION_METHOD_BIAS = "IC.  Does that mean that the
>>>> radiometric corrections have already been applied? In the metadata file
>>>> from
>>>> GLCF's website it does say END_GROUP = CORRECTIONS_APPLIED
>>> MOST GLCF FILES ARE ALREADY CORRECTED AND DON'T REALLY REQUIRE ANY POST
>>> PROCESSING
>>>
>>>
>>>> 3. When I  patch, say band 4 of  2 scenes I find a distinct difference 
>>>> in
>>>> the intensity/brightness of the 2 scenes.  The sun elevation and sun
>>>> azimuth
>>>> are different in these 2 scenes? Is that the reason for difference in
>>>> brightness? If so, how does one change the sun elevation and azimuth 
>>>> for
>>>> one
>>>> scene?
>>> YOU CAN'T CHANGE THE SUN ELEVATION AND AZIMUTH OF THE SHOT, IT IS FIXED
>>> WHEN THE
>>> IMAGE WAS TAKEN.  YOU CAN TRY TO FIND DIFFERENT LANDSAT IMAGES FROM
>>> DIFFERENT
>>> TIMES THAT MIGHT MATCH, BUT IT RARELY WORKS OUT THAT YOU CAN FIND THAT.
>>>
>>>
>>>> 4. One final question-- is there a program which accurately converts
>>>> latitude longitude into UTM coordinates?
>>>
>>> GRASS DOES THIS QUITE WELL (V.PROJ, R.PROJ) OR YOU CAN USE GDAL.
>>>
>>> G'luck
>>> -Ian
>>>
>>
>>
>
>
>