Thanks Micha for your help but I got an error while doing this 1- Create new empty vectorial 2- run v.db.addtable command that you kindly sent me 3- use v.digit as defined previously 4- Inside tcltk's digitizing menu select Digitize new Centroid 5- Leave layer as 1 6- Change Mode to Manual Entry 7- First digitize boundary (by selecting boundary) by selecting points with left-mouse-button and close polygon with right-mouse-button 8- A panel with "FORM" title appears with a tab saying Attributes saying: "New record was created" saying CAT : 1 (this cat refers to the land cover category right?); train_lbl value and GRASSRGB; 9- I place the values (water,1) for train_lbl and GRASSRGB 10- a box ask me for "ASSUME DATA ENCODING AS" a list appears. I should select which one? ASCII? 11- In trhis case I select ASCII and press SUBMIT. In the bottom of that box "Record successfully updated" appeared. 12- Insert centroid-1 and press submit in "Form" panel 13- Did the same for a few more polygons of cat 1 14- Did the same for a few more polygons of cat 2 and 3 15- Pressed Save and Exit
Then I realized that at my v.digit panel command output I had this warning in there: *Could not set Tcl system encoding to 'ascii' (unknown encoding "ascii")* *Unable to read vector map* Questions: 1- Is this the right procedure? 2- What encoding should I use? 3- Regarding GRASSRGB field, what information usually you place in there? Color code or color description? 4- For Supervised classification algorithms in GRASS, Vector type (accessible by using Query raster/vector tool) should be Boundary? Because, for instance, if I press a defined boundary, in some places I get Type: AREA and in others: Boundary (as shown bellow) (...) Map: vector06 Mapset: landsat Type: Boundary Id: 9 Layer: 1 Category: 3 Driver: dbf Database: C:\GRASS6\grassdata/North-Carolina/landsat/dbf/ Table: vector06 Key column: cat cat : 3 train_lbl : urban GRASSRGB : 3 (Thu Jun 17 10:34:04 2010) Command finished (0 sec) (Thu Jun 17 10:34:06 2010) v.what --q -a map=vecto...@landsat east_north=639279.744997,227730.071998 (...) Map: vector06 Mapset: landsat Type: Area Sq Meters: 2158429.741 Hectares: 215.843 Acres: 533.360 Sq Miles: 0.8334 Layer: 1 Category: 3 Driver: dbf Database: C:\GRASS6\grassdata/North-Carolina/landsat/dbf/ Table: vector06 Key column: cat cat : 3 train_lbl : urban GRASSRGB : 3 Thanks for your help and support Jenny On Wed, Jun 16, 2010 at 7:59 PM, Micha Silver <[email protected]> wrote: > On 06/16/2010 06:55 PM, Jenny Turner wrote: > > 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? > > All the above looks good. > > 5- And for each Centroid I select a Cat right? > > Yes, always using the *same* cat for training areas of the same type. > > (Is this the proceeding?) > > About this, I have two questions: > a- I have to leave "Insert New record into table" checked right? > > Yes > > 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? > > Ah, v.db.addtable vector00 col="train_lbl varchar(16), GRASSRGB > varchar(16)" > THis should setup an attrib table with two columns, one for a label and one > for an RGB color for the training area. > > c- When I press the image a point is created but how can I define the > boundaries of the centroid? > > First digitize the boundary. Here you need not enter any attributes. The > cat values are also not relevant. > NExt digitize a centroid inside each boundary. Give each centroid a cat > value that matches the type of training area. So all the forests will be i.e > cat=1, and all the urban will be i.e cat=10, etc. > > > > 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 >> >> > > This mail was received via Mail-SeCure System. > > > > -- > Micha Silver > Arava Development Co. +972-52-3665918 > http://surfaces.co.il > >
_______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
