Hi Micha and GRASS-users/list Let me see if I get this straight 1- use v.digit (e.g. v.digit -n map=vector00 bgcmd=d.rast map=lsat5_1987_40 ) 2- Inside tcltk's digitizing menu select Digitize new Centroid 3- Leave layer as 1? 4- Change Mode to Manual Entry? 5- And for each Centroid I select a Cat right? (Is this the proceeding?)
About this, I have two questions: a- I have to leave "Insert New record into table" checked right? b- After I left "Insert New record into table" checked, Layer 1 and Cat 1 and Mode: Manual Entry, when I presss in the image a Error Window appeared stating: Database table for this layer is not defined. Where shall i define the database table for a new vectorial that I digitizing? c- When I press the image a point is created but how can I define the boundaries of the centroid? Thanks Jenny On Wed, Jun 9, 2010 at 7:06 PM, Micha Silver <[email protected]> wrote: > polygon to a certain category? > > This indeed is not obvious. What I've done is change the category mode from > "Next not used" to "Manual entry". This is set in the lower part of the > v.digit window (in tcltk interface). Now each time you digitize a *centroid* > for a training area, set its cat value to some standard value you choose. > For example, you might decide: > train_area cat > ------------------------ > forest 1 > agriculture 2 > urban 9 > water 10 > .... > > Now for each training polygon which is a forest, set the cat value of its > centroid to 1, agri areas will get value 2, and so on for all the centroids > of all the training polygons. (Note that the cat values for the boundary > lines are pretty much irrelevant in GRASS's vector model). > > When you're done digitizing training areas, you might add another column or > two to the attrib table for the training areas - > v.db.addcol train_areas col="train_label varchar(16), RGBCOLOR varchar(16)" > then give each centroid cat value a suitable label and an RGB color combo, > etc. Makes life easier down the line... > > > This mail was received via Mail-SeCure System. > > > _______________________________________________ > grass-user mailing > [email protected]http://lists.osgeo.org/mailman/listinfo/grass-user > > This mail was received via Mail-SeCure System. > > > > > > -- > Micha Silver > Arava Development Co. +972-52-3665918http://www.surfaces.co.il > >
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