[GRASS-user] RE: Hidrological network (ALT SHN)

[Shane Litherland]

Hi Andr,

You mention that you have streams of different 'order', does that mean
you have a table connected with a column containing a value for each bit
of stream (e.g. the river and tributaries are a combination of vector
lines, and each line between one stream junction and the next has a
'stream order' number)?

If so, could you do something as simple as putting a sql query in the
'where' box of the properties dialog (on the 'selection' tab)? e.g.
(where) stream_order_column<4
?
This has worked for me when viewing a stream-order vector map with
appropriate values.
(this properties tab is the gui for d.vect, if you're looking for it by
other means)

I am not sure if, after that stage, you may be able to save a copy of
that vector with the same 'where' criteria applied during the copy
process, to then have a smaller vector file for your own use. Or copy
the entire vector then delete/drop the vectors (and attributes from
table) for the higher-order streams you don't want?

Any other thoughts on this one people? or am I paddling up the wrong
stream, so to speak?

-shane.