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On 06/16/2010 06:55 PM, Jenny Turner wrote:
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">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-family: 'Times New Roman'; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal; font-size-adjust: none; font-stretch: normal; -x-system-font: none;"> </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>
</blockquote>
All the above looks good.<br>
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">
<div>5- And for each Centroid I select a Cat right?</div>
</blockquote>
Yes, always using the *same* cat for training areas of the same type. <br>
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">
<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>
</blockquote>
Yes<br>
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">
<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>
</blockquote>
Ah, v.db.addtable vector00 col="train_lbl varchar(16), GRASSRGB
varchar(16)"<br>
THis should setup an attrib table with two columns, one for a label and
one for an RGB color for the training area.<br>
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">
<div>c- When I press the image a point is created but how can I
define the boundaries of the centroid?</div>
</blockquote>
First digitize the boundary. Here you need not enter any attributes.
The cat values are also not relevant.<br>
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.<br>
<br>
<blockquote
cite="mid:AANLkTimgW3laFu9DSCz_8Y5dwM5VhI90hMSX0rBHX5B1@mail.gmail.com"
type="cite">
<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 moz-do-not-send="true"
href="mailto:micha@arava.co.il">micha@arava.co.il</a>></span> wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div text="#000000" bgcolor="#ffffff">
<div>
<div class="h5">
<blockquote type="cite">
<div><font face="monospace">polygon to a certain category? <br>
</font></div>
</blockquote>
</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>
</font>
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</blockquote>
<font face="monospace"><br>
<br>
</font>
<pre cols="72"><font face="monospace">--
Micha Silver
Arava Development Co. +972-52-3665918
<a moz-do-not-send="true" href="http://www.surfaces.co.il"
target="_blank">http://www.surfaces.co.il</a>
</font></pre>
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</blockquote>
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<br>
<pre class="moz-signature" cols="72">--
Micha Silver
Arava Development Co. +972-52-3665918
<a class="moz-txt-link-freetext" href="http://surfaces.co.il">http://surfaces.co.il</a>
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