Hi, I fear OpenJUMP cannot stop rendering and I even if it could I am not sure if it could make PostGIS to stop handling some lunatic "SELECT * from ten_million_parcels". The option could be useless sometimes, but I do use the similar system with a few WMS layers on our Mapserver. For example, I am drawing at maximum 300 lakes ordered by size, or not more than 500 field parcels. With parcels I am selecting at certain scales only those with ID ending with two zeros or with a bit closer zoom ID ending with one zero for making the selected 500 parcels to spread over the whole BBOX area. But that's perhaps for more advanced use. However, we may know that 200000 parcels will make OpenJUMP to run out of memory and then getting just a part of the features (but fast) would be better that wait a long time and finally see only a memory heap error.
-Jukka Rahkonen- ________________________________ Lähettäjä: G. Allegri [gioha...@gmail.com] Lähetetty: 11. lokakuuta 2011 19:50 Vastaanottaja: OpenJump develop and use Aihe: Re: [JPP-Devel] Add feature count limit to dynamic PostGIS layers I don't know if it's possible with OJ, but with many other GIS softwares the user has the possibility to pause rendering (and reading data), adjust zoom levels, symbology, etc., the start rendering again. I fear that a feature count limit is quite useless depending on the sequence in which data rows are mantained: they could be spatially sequential (in some way) but they could be spatially sparse. Let's suppose they start sequencially from top-left BBOX: in this case you would render only a region of the whole dataset, and you may miss the area you're interested in... my 2 cents, giovanni 2011/10/11 Rahkonen Jukka <jukka.rahko...@mmmtike.fi<mailto:jukka.rahko...@mmmtike.fi>> Hi, What do you think, would it be too dangerous to add a possibility to set a feature count limit for PostGIS datastore layers? I know I can set scale limit for the layer but if I have zoomed to show the whole country when adding some layer with millions of features into OpenJUMP is starts to read the whole PostGIS table and chokes before it is possible to set the scale limit. What is dangerous is that user would not always have all the data from the PostGIS layer on the visible map. Perhaps there should be a red light burning and warning the user that there is a count limit set for the layer? Even better if the light burns only if the feature limit has been reached. Technically it should not be difficult to set the feature count, just to add "limit [max_features]" to all the SQL queries if the parameter is set. -Jukka Rahkonen- ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2d-oct _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net<mailto:Jump-pilot-devel@lists.sourceforge.net> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2d-oct _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
