[GRASS-dev] [bug #5254] (grass) enable v.what to report on more that one category

Hamish hamish_nospam at yahoo.com
Fri Nov 3 00:36:45 EST 2006

Request Tracker wrote:
> this bug's URL: http://intevation.de/rt/webrt?serial_num=5254
> ---------------------------------------------------------------------
> Subject: enable v.what to report on more that one category
> Platform: GNU/Linux/x86
> A wish for Grass 6.3?
> I don't know how often situations like this might arise, however...
> I have a database with over 75000 records (~30 fields/record) which is
> poorly georeferenced (it uses an odd alpha-numeric mapping reference
> involving map book pages, etc), such that locations can be defined
> only to the nearest 1km by 1km area. I have calculated UTM centered on
> the 1 km squares for each record using a spreadsheed. These 75000
> records imported into Grass result in approx. 12500 points (too much
> data to sort on a spreadsheet).
> While some data points may contain as many as 20 categories, it
> appears that v.what can report on only one category (the first one
> encountered?). It would be nice if v.what could "drill through" all
> categories at each point to report all data. In addition, it would be
> nice if a new Grass module could be developed to allow functions like
> mean, max, min, etc., to be done for the various fields available in
> this too-many-categories-per-point database, in which case some very
> useful surface maps could be produced.
> I do not write code and so cannot contribute directly to development,
> but I introduce the concept here in the hope that someone who can
> write might find this change to v.what and/or a new function handy. I
> am willing to make parts of the database available for such
> development and can participate in testing.

does v.perturb help to get the points directly off the top of one
another? if error is +/- 500m anyway, introducing a few cm won't harm..


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