[GRASSLIST:433] Re: m.in.e00 question

[Michel Wurtz]

Keith J. Forbes wrote:
> FLAG: Set the following flag?
>     Link attributes by coverage-ID not by coverage-#?
> 
> 
> Question: What exactly does this option mean?
> 

Each feature in e00 file (and in Arc/Info) have an internal
identifier (name_of_layer-#) to link attributes and geometry.
It is however a bad practice to use this number as an external
link because the internal numbering may change if you do
some operation (cleaning after erasing some objects, etc.).
# is computed automaticaly and you cannot modify it.
There is another identifier (name_of-layer-ID) that is
entirely controled by the user, and can therefore be used
to link your coverage to an external database, etc...

In practice for m.in.e00 :
- the is one attribute entry per graphic object (line, area, point)
so you should use the normal behaviour of the program.
- in some case, you want to consider all objects having the
same ID as one object in Grass, or the # links are broken
(yes, sometimes you can get really bad datasets !), so you
may want to try the ID number.

Honestly, its also an historical feature : the first release
used (incorrectly) ID for the link...

-- 
Michel Wurtz - Auzeville-Tolosane