[GRASS-user] Re: highest and lowest point in catchment

[Dr. Manuel Seeger]

Thanks Richard,
but elevation data is on a raster map.
The idea I had was to generate point vector files with the highest and 
lowest point and then generate the colums with y and y coordinates... 
but it seems to me like a complicated way and I was wondering if there 
is a possibility to do that with r.mapcalc.... I think the functions are 
ther, but how combining?

Perhaps someone knows a way?

Thanks
MAnuel

Richard Chirgwin schrieb:
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>> Today's Topics:
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>>    1. highest and lowest point in catchment (Dr. Manuel Seeger)
>>    2. SHELL Variable problem: Workaround (Peter L?we)
>>    3. Re: SHELL variable not set (Martin Wegmann)
>>    4. Re: SHELL variable not set (Glynn Clements)
>>    5. Re: SHELL variable not set (Hamish)
>>    6. Re: SHELL variable not set (Markus Neteler)
>>    7. Re: Building wxgrass vdigit (Martin Landa)
>>    8. segment_format error with r.watershed (Wes Kent)
>>    9. union features of vector (Alfredo Alessandrini)
>>   10. Re: Snap across layers (Martin Landa)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 29 Jan 2008 10:01:20 +0100
>> From: "Dr. Manuel Seeger" <seeger at uni-trier.de>
>> Subject: [GRASS-user] highest and lowest point in catchment
>> To: GRASSLIST <grass-user at lists.osgeo.org>
>> Message-ID: <479EEB60.6050606 at uni-trier.de>
>> Content-Type: text/plain; charset=ISO-8859-15; format=flowed
>>
>> Hello all,
>> I hope the questions does not seem too simple, but I have now no real 
>> good idea how to solve this simple problem:
>>
>> I need to find the highest and the lowest point within catchments 
>> WITH their coordinates (and to get the information about altitude and 
>> coordinates, of course)
>>
>> thanks for hints!
>>
>> manuel
>>
>>   
> Manuel - hope I'm not being silly here, but I'd consider just using an 
> SQL select directly to the data store.
>
> Select max( <altitude column> ), <latitude column>, <longitude 
> column>, <any other column you want> from <table> where <boundary 
> conditions of catchment>
> Select min( <altitude column> ), <latitude column>, <longitude column> 
> <any other column you want> from <table> <boundary conditions of 
> catchment>
>
> If you have to, you could extract only the catchment to a separate 
> vector, so that you don't need to fool around with complex boundary 
> conditions.
>
> But I'm sure that a genuine Grass expert will have a simpler solution 
> than this ...
>
> Cheers,
> Richard
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-- 

_______________________________________________________________________
Dr. Manuel Seeger
Wiss. Assistent 			Scientific Assistant
Physische Geographie 			Dpt. of Physical Geography
FB VI - Geographie/Geowissenschaften 	Geography/Geosciences
Universität Trier			University of Trier
D - 54286 Trier
Tel.:	+49-651-201 4557
Fax:	+49-651-201 3976
Web:	http://www-neu.uni-trier.de/index.php?id=9607