[GRASSLIST:419] Re: a huge matrix ?

[orkun]

H Bowman wrote:

>>>The most straightforward approach (although not particularly
>>>efficient), would be to use an iterative approach, i.e.
>>>
>>>	n=0
>>>	last='null()'
>>>	while read a1 a2 a3 a4 a5 a6 a7 a8 ; do
>>>		result=pr2.pass$n
>>>		r.mapcalc "$result = if (f28geo5==$a1 && f28slpcat==$a2 && f28concavity==$a3 && n_facing==$a4 && road_bas==$a5 &&str_buf==$a6 && f28f4==$a7, $a8, $last)"
>>>		last=$result
>>>	done < rules.txt
>>>
>>>where rules.txt looks like:
>>>
>>>	21 6 1 1 1 1 0 701.22
>>>	 7 4 2 1 1 2 1 702.06
>>>	...
>>>
>>>      
>>>
>>Firstly I intend to try your iterative way.
>>In that,  doesn't n have any increament ?
>>something like n=n+1 in the loop.
>>If so,Doesn't  it mean creating a new map - totally 10500 map-  in every 
>>iteration
>>    
>>
>
>Not sure if this is what you are after, but as a general iterative bash scripting template:
>
>n=0
>r.mapcalc patchmap="null()"
>while read a1 a2 a3 a4 a5 a6 a7 a8 ; do
>	echo "Pass $n .."
>	r.mapcalc ...
>	r.patch out=patchmap in=patchmap,pr2.pass$n (?? r.mapcalc sum=sum+new ..)
>	g.remove rast=pr2.pass$n
>	n=`expr $n + 1`
>done
>
>
>actually for that n isn't needed, but still a good idea.
>
>
>Hamish
>
>
>  
>
thank you

adding maps then deleting maps  created previously is very good idea to 
maintain harddisk space.

kind regards



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