Hi Micha and GRASS-users/list<div><br></div><div>Let me see if I get this straight</div><div>1- use v.digit (e.g. <span lang="PT"><span><span style="font: normal normal normal 7pt/normal 'Times New Roman'; "> </span></span></span><span lang="PT">v.digit -n map=vector00 bgcmd=d.rast map=lsat5_1987_40 )</span></div>
<div><span lang="PT">2- Inside tcltk's digitizing menu select Digitize new Centroid</span></div><div><span lang="PT">3- Leave layer as 1?</span></div><div>4- Change Mode to Manual Entry?</div><div>5- And for each Centroid I select a Cat right?</div>
<div>(Is this the proceeding?)</div><div><br></div><div>About this, I have two questions:</div><div>a- I have to leave "Insert New record into table" checked right?</div><div>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?</div>
<div>c- When I press the image a point is created but how can I define the boundaries of the centroid?</div><div><br></div><div>Thanks</div><div>Jenny</div><div><br><br><div class="gmail_quote">On Wed, Jun 9, 2010 at 7:06 PM, Micha Silver <span dir="ltr"><<a href="mailto:micha@arava.co.il">micha@arava.co.il</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div text="#000000" bgcolor="#ffffff"><div><div></div><div class="h5"><blockquote type="cite"><div><font face="monospace">polygon to a certain category? <br>
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</div></div><font face="monospace">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:<br>
train_area cat<br>
------------------------<br>
forest 1<br>
agriculture 2<br>
urban 9<br>
water 10<br>
....<br>
<br>
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).<br>
<br>
When you're done digitizing training areas, you might add another
column or two to the attrib table for the training areas - <br>
v.db.addcol train_areas col="train_label varchar(16), RGBCOLOR
varchar(16)"<br>
then give each centroid cat value a suitable label and an RGB color
combo, etc. Makes life easier down the line... <br>
<br>
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<pre cols="72"><font face="monospace">--
Micha Silver
Arava Development Co. +972-52-3665918
<a href="http://www.surfaces.co.il" target="_blank">http://www.surfaces.co.il</a>
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