<span class="Apple-style-span" style="font-family: arial, sans-serif; font-size: 13px; background-color: rgb(255, 255, 255); "><div><div><font face="arial, helvetica, sans-serif">Hello GRASS Community,</font></div><div><font face="arial, helvetica, sans-serif"><br>
</font></div><div><font face="arial, helvetica, sans-serif">I'm having a problem that I'm hoping you can help me find the source of.</font></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div>
<font face="arial, helvetica, sans-serif">I think that either A) I am trying to use the v.generalize tool incorrectly, B) that my data has some sort of topological problem which I'm unaware of, or C) that there is a bug in v.generalize. The simplest way to describe what's happening is that I am consistently unable to generalize a large group of contiguous polygons (African states most recently) without losing a large number of polygons from my data. I have tried a variety of different things, all without success, and now I'd like to ask if someone would be willing to verify that what I'm seeing isn't a problem of my own creation. </font>I've posted my data files at <a href="https://owa.postoffice.net/owa/redir.aspx?C=f8a443413bdc4a4a9a4edb8bbe3f24bf&URL=http%3a%2f%2fwww.macrogis.net%2fafrica" target="_blank" style="color: rgb(0, 0, 204); ">www.macrogis.net/africa</a>, along with a before-and-after image of the specific problem I've encountered. I'm using GRASS v 6.4.1 which I downloaded from the main website 2 months ago. The commands I have used are the following:</div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">v.in.ogr dsn=africa_clean.shp</font></div><div><font face="arial, helvetica, sans-serif">v.clean tool=rmarea type=boundary thresh=200000000 in=africa_clean out=africa_clip</font></div>
<div><font face="arial, helvetica, sans-serif">v.generalize type=boundary method=lang threshold=.015 look_ahead=11 in=africa_clip out=africa_general</font></div></div><div><font face="arial, helvetica, sans-serif"><br></font></div>
<div><font face="arial, helvetica, sans-serif">Note: I know that I am removing small polygons with the v.clean operation. My concern is with the many missing contiguous polygons in the main part of the continent.</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Thanks in advance for any help you can provide,</font></div><div><font face="arial, helvetica, sans-serif"><br>
</font></div><div><font face="arial, helvetica, sans-serif">Roger</font></div><div><font face="arial, helvetica, sans-serif">--</font></div></span>