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<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000>Hi,</FONT></SPAN></DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000></FONT></SPAN> </DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New" color=#800000>I am
trying to add a column to my table that lists the centroids the polygon
described in the 'the_geom' field. I use the following, which works
(I think), but of which I have questions:</FONT></SPAN></DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000></FONT></SPAN> </DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000>SELECT AddGeometryColumn( '', 'shp_mcd', 'centroid', -1, 'POINT',
2 );<BR>UPDATE shp_mcd SET centroid = centroid ( the_geom );</FONT></SPAN></DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000></FONT></SPAN> </DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New" color=#800000>My
question is about the final argument to AddGeometryColumn. Documentation
states that centroid() returns a POINT. I figure that that implies that
the last argument should then be a 0, not a 2. But if I use a 0 in the
last field, the updated doesn't work -- it tells me that i violate a dimension
constraint. Can someone explain why I need to have a 2 as the last
argument and not a 0? It doesn't make sense to me.</FONT></SPAN></DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000></FONT></SPAN> </DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000>Thanks,</FONT></SPAN></DIV>
<DIV><SPAN class=090575918-21112006><FONT face="Courier New"
color=#800000>Matt</FONT></SPAN></DIV></BODY></HTML>