Paul, Steve,<br><br>Thanks for the quick replies, unfortunately it's pretty hard to tell from those images if they match.<br><br>I've done some more digging and it turns out that these shapes were created in Arcview 3.x. The notes I have say...
<br><br>> This approach selects a number of the outliers and joins the extreme points using elliptical arcs. <br>> The arcs are all created in a direction moving out from the store.<br><br>However, I dont see customer points at the discontinuities in the hulls, so it appears that the "extreme points" are perhaps interpolated.
<br><br><br>Will<br><br><div><span class="gmail_quote">On 7/5/06, <b class="gmail_sendername">Paul Ramsey</b> <<a href="mailto:pramsey@refractions.net">pramsey@refractions.net</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
William,<br><br>It doesn't look like this is a standard algorithm, but more likely a<br>particular empirical technique provided by the particular software you<br>were using. So substituting some other technique might yield a
<br>different shape entirely... do any of the techniques mentioned here<br><<a href="http://www.geospatial-online.com/geospatialsolutions/article/articleDetail.jsp?id=1348">http://www.geospatial-online.com/geospatialsolutions/article/articleDetail.jsp?id=1348
</a>><br>sound like what was done to your data?<br><br>Paul<br><br>William Andersen wrote:<br>><br>> I'm fairly new to postgis, and working to automate a number of<br>> processes.<br>><br>> We are trying to compute market area polygons that look like the
<br>> attached image. These were created by some older software.<br>><br>><br>> They are referred to as Amoeba Hulls, and they contain 80% of a<br>> store's customers. However I can't find any solid documentation that
<br>> would allow me to reproduce them.<br>><br>> Does anyone have any ideas how these shapes are created or an<br>> alternate name that I might be able to google? Additionally, we may<br>> be in a position to finance the development of this feature.
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