Hello Adam, maybe another solution in this case would be a set of 2 tables : * one linking to the geometry, that is containing nothing but cat values, * another one, containing a cat column (related to the "geometric" table) and different data columns corresponding to your sampling.
Does this help ? VB Le lundi 13 avril 2009 à 14:23 -0700, Adam Dershowitz a écrit : > I am trying to set up a new project in Grass, and I have a question > about the best approach. > I have different vector locations, and at each one there were multiple > samples taken. At the moment I have each sample as a row in a data > base. > My question is how best to put this data into a set of vector points. > I believe that I can do it in either of two ways (of not others). > 1) I can create a vector point at each location, then I think that I > can have multiple cats for that object. So I think I can do cat=1,3,6 > for a given location. > Will that work OK? > 2) I can just create different vector objects, that happen to be at > the identical location, and have each one point to a different cat. > > If the above is not clear, here is a bit more detailed example. > At location A there was a sample collected on 1/1 with a value of 2.1, > on 2/2 with a value of 2.2 and on 3/3 with a value of 3.3 > > The above data is already 3 rows in a database. > > I want to be able to display data about point A (say, average value or > things like that). Should I just create a vector point A and then do > cat=1,2,3 or should I create 3 different vector points at A, each one > having a different cat? > > Any guidance about the benefits or limitations each approach (or any > other approach to consider) would be greatly appreciated. > > Thanks, > > --Adam > > > > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user