<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><div>The performance impact is not TERRIBLE but that also depends on hardware capability and user load. Even serving 200+ layers, not every user is requesting every layer for every map draw.</div><div><br></div><div>Web Mercator is okay, but there are also other projections that look good at that particular spot in the country (I'm thinking something in the neighborhood of an Albers Equal Area Conic). If your main calculation is based on water bodies within a certain distance then you may very seriously consider storing the data in a different projection, otherwise the calculation that does the radius based search will need to do something like this:</div><div><br></div><div>1) Project the center to something in meters or feet.</div><div>2) Buffer that point.</div><div>3) Project the resulting
polygon in to WGS84</div><div>4) Then do the search.</div><div><br></div><div>This is all assuming you're looking for absolute correctness... If Brent isn't too busy he might chime in as I know he stores everything in WGS84 and reprojects it on the fly.</div><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><br><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font size="2" face="Tahoma"><b><span style="font-weight: bold;">From:</span></b> Dara Olson <dolson@glifwc.org><br><b><span style="font-weight: bold;">To:</span></b> Dan Little <danlittle@yahoo.com>; geomoose-users@lists.sourceforge.net<br><b><span style="font-weight: bold;">Sent:</span></b> Tue, April 27, 2010 1:58:36 PM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Geomoose-users] Setting buffer select
units<br></font><br>
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<div><font face="Garamond">We are using GeoMoose 2.2. Our data
covers three states (Michigan, Minnesota & Wisconsin), so we have all
of our postgis data in WGS84. We want to
eventually view the data in webmercator, but we are concerned
with speed/performance because we would be reprojecting a lot of layers on the
fly. Currently we have over 200 layers with many more layers to be
added. Will reprojecting that many layers significantly effect
performance? Or would it be better to decrease accuracy in measuring
distance and calculating acreage because of the projection (WGS84)?
We would using the buffer tool for selecting waterbodies within a certain
distance. Any thoughts or suggestions would be greatly
appreciated!</font></div>
<div><font face="Garamond">Miigwech!</font></div>
<div><font face="Garamond">Dara </font></div>
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<div style="FONT:10pt arial;">----- Original Message ----- </div>
<div style="FONT:10pt arial;BACKGROUND:#e4e4e4;"><b>From:</b>
<a rel="nofollow" title="danlittle@yahoo.com" ymailto="mailto:danlittle@yahoo.com" target="_blank" href="mailto:danlittle@yahoo.com">Dan Little</a>
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<div style="FONT:10pt arial;"><b>To:</b> <a rel="nofollow" title="dolson@glifwc.org" ymailto="mailto:dolson@glifwc.org" target="_blank" href="mailto:dolson@glifwc.org">Dara Olson</a> ; <a rel="nofollow" title="geomoose-users@lists.sourceforge.net" ymailto="mailto:geomoose-users@lists.sourceforge.net" target="_blank" href="mailto:geomoose-users@lists.sourceforge.net">geomoose-users@lists.sourceforge.net</a>
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<div style="FONT:10pt arial;"><b>Sent:</b> Tuesday, April 27, 2010 11:54
AM</div>
<div style="FONT:10pt arial;"><b>Subject:</b> Re: [Geomoose-users] Setting
buffer select units</div>
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<div>Hm.. yes, there is. What version of GeoMOOSE are you using?
Is there any chance you can use a meters-based projection instead?
By doing the conversion from DD to a measure unit is a real fallacy
because it changes DRASTICALLY based on where on the planet the user is trying
to measure.</div>
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<div style="FONT-FAMILY:times new roman, new york, times, serif;FONT-SIZE:12pt;"><font size="2" face="Tahoma"><b><span style="FONT-WEIGHT:bold;">From:</span></b> Dara
Olson <<a rel="nofollow" ymailto="mailto:dolson@glifwc.org" target="_blank" href="mailto:dolson@glifwc.org">dolson@glifwc.org</a>><br><b><span style="FONT-WEIGHT:bold;">To:</span></b> <a rel="nofollow" ymailto="mailto:geomoose-users@lists.sourceforge.net" target="_blank" href="mailto:geomoose-users@lists.sourceforge.net">geomoose-users@lists.sourceforge.net</a><br><b><span style="FONT-WEIGHT:bold;">Sent:</span></b> Tue, April 27, 2010 11:05:27
AM<br><b><span style="FONT-WEIGHT:bold;">Subject:</span></b>
[Geomoose-users] Setting buffer select units<br></font><br>
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<div><font face="Garamond">Is there a way to set buffer select units different
than the ground units defined in the mapbook? I am using WGS84 (4326)
and would like to buffer select based on meters, feet or miles and not
degrees.</font></div>
<div><font face="Garamond">Any help would be greatly appreciated.</font></div>
<div><font face="Garamond">Dara</font></div></div></div></blockquote>
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