Hi, We are working with a bit similar data right now. Myself I do not think that drawing all the points is the best way for showing their distribution if points are so dense that the rendered dots start to overlap. Let's say the symbol is 6 pixel wide red dot. If there are observations in the data 6 pixel apart each other the map will be painted all red. User will see no difference with places where observations are one 1 pixel apart. We aim at making heathmaps from our observation data instead. Grouping the amount of observations and draw the groups with variable size symbols was another approach but heatmaps suit better with our data because we want also visualize the amount of damage from the attribute data.
I did do some experiments a few years ago and my conclusion was that there are no need to draw more than a few thousand features (parcels in that case) on a screen because there are not really enogh many pixels to show them all and painting same pixels many times is just waste of time. However, the sample must show a similar distribution than the original data. If distribution is uneven and there can be, let's say, a big accident in a very isolated place and it should show on a map at any scale then it would be bad if it drops out from the sample. I can make a test next week with our Oracle next week. Hypothesis is that if table has 50000 rows then rendering everything is fast, but if I render a table with 150000 rows then it will take more than three times longer. -Jukka Rahkonen- cheesybiscuits wrote: > Yukka: unfortunately yes, at this point it is necessary to draw all the points. I have to show their distribution so I can't hide some and show others as it would misrepresent the overall shape. As their locations frequently change it is not feasible to calculate any of this in advance and calculating on the fly would presumably incur a higher performance cost. > However, even if I could reduce the number of points displayed the performance question - and whether this is typical - still stands. > cholmes: I might be able to try this, or test with a Shapefile, but Oracle is already in place as the operational database and there is no scope to change it. Do you have any suggestions on where I might find more information about these bottlenecks? > Also I'm a bit confused about how Oracle would affect rendering performance if what I think it happening is true - after Oracle finds all the data it takes GeoServer 5 seconds to display it and Oracle does very little until the connection is closed - am I missing something here? > Thanks both for your input -- View this message in context: http://osgeo-org.1560.n6.nabble.com/5-seconds-to-render-130-000-points-typical-GeoServer-WMS-performance-tp4995984p4996023.html Sent from the GeoServer - User mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Geoserver-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geoserver-users ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Geoserver-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geoserver-users
