<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">That is the name you are giving the index. It is good practice for the
name to include the table & column(s) the index applies to in the
name you give it.<br><br>--- On <b>Wed, 2/15/12, Bistrais, Bob <i><Bob.Bistrais@maine.gov></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Bistrais, Bob <Bob.Bistrais@maine.gov><br>Subject: Re: [postgis-users] advice for quicker display?<br>To: svm@clevelandmetroparks.com, "PostGIS Users Discussion" <postgis-users@postgis.refractions.net><br>Date: Wednesday, February 15, 2012, 8:32 AM<br><br><div class="plainMail">OK, so it sounds like I need to create the index for starters (and not<br>bother with the layer at full scale).<br><br>As far as creating the index, is mytable_the_geom_gidx an existing<br>column, or the name of a new one? <br><br><br>-----Original Message-----<br>From: <a ymailto="mailto:postgis-users-bounces@postgis.refractions.net"
href="/mc/compose?to=postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net</a><br>[mailto:<a ymailto="mailto:postgis-users-bounces@postgis.refractions.net" href="/mc/compose?to=postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net</a>] On Behalf Of<br>Stephen V. Mather<br>Sent: Tuesday, February 14, 2012 2:26 PM<br>To: 'PostGIS Users Discussion'<br>Subject: Re: [postgis-users] advice for quicker display?<br><br>To expand on that, the basic understanding is that file level access to<br>data<br>(e.g. shapefile) will always be faster for the entire dataset (all<br>things<br>being equal) because of the management overhead of the database, but for<br>accessing a subset of features of the dataset (often the typical use<br>case),<br>the database is faster if it has indices on the appropriate columns (the<br>geometry being the more important one). Even if you are accessing
all<br>of<br>the records in the database at once as a common case, you probably don't<br>need every node in the polygons/polylines, and might create a view or<br>column<br>that pre-generalizes those data before delivering them.<br><br>Best,<br>Steve<br><br>Stephen Mather<br>Geographic Information Systems (GIS) Manager<br>(216) 635-3243<br><a ymailto="mailto:svm@clevelandmetroparks.com" href="/mc/compose?to=svm@clevelandmetroparks.com">svm@clevelandmetroparks.com</a><br>clevelandmetroparks.com<br><br><br><br><br>-----Original Message-----<br>From: <a ymailto="mailto:postgis-users-bounces@postgis.refractions.net" href="/mc/compose?to=postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net</a><br>[mailto:<a ymailto="mailto:postgis-users-bounces@postgis.refractions.net" href="/mc/compose?to=postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net</a>] On Behalf
Of<br>Stephen<br>Woodbridge<br>Sent: Tuesday, February 14, 2012 2:15 PM<br>To: <a ymailto="mailto:postgis-users@postgis.refractions.net" href="/mc/compose?to=postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br>Subject: Re: [postgis-users] advice for quicker display?<br><br>On 2/14/2012 1:57 PM, Bistrais, Bob wrote:<br>> As some of you already know, I'm a newbie to PostGIS and have just<br>> barely got a test PostGIS database up and running. So, my latest<br>> question is in regards to draw times. I created a statewide parcel<br>layer<br>> from a shapefile. At statewide scale, when the application loads, the<br>> parcel data draws far slower than the original shapefile did. How can<br>I<br>> tune this so that draw times are better?<br><br>If you are drawing all the data, it will always be slower than <br>shapefiles. The trick is to not draw more than is reasonable at a given <br>scale. So the answer is
don't try to draw all the parcels for the whole <br>state. As you zoom in and need to only draw a subset of the parcels, you<br><br>will start to get speed advantages by using the spatial (GIST) indexes <br>in postgis.<br><br>create index mytable_the_geom_gidx on mytable using gist (the_geom);<br><br>-Steve W<br>_______________________________________________<br>postgis-users mailing list<br><a ymailto="mailto:postgis-users@postgis.refractions.net" href="/mc/compose?to=postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br><a href="http://postgis.refractions.net/mailman/listinfo/postgis-users" target="_blank">http://postgis.refractions.net/mailman/listinfo/postgis-users</a><br><br><br><br>_______________________________________________<br>postgis-users mailing list<br><a ymailto="mailto:postgis-users@postgis.refractions.net"
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