[Chameleon] RE: LocateByAttribute highlighting issues

Gambin Dejan Dejan.Gambin at pula.hr
Wed Apr 5 04:10:51 EDT 2006


Sorry it was my fault...I have used the wrong layer for searching
(ANNOTATION) so the layer was POINT not LINE. Regarding the first
problem of not highlighting the whole set, it seems that sometimes label
covers the line (labels are sometimes wide and line is short) so I think
it is OK now.

Regarding the speed, the slowest thing is happening after showing the
results table, when the new queryresult shapefile is being drawn on the
map. This can be pretty slow. I suppose this can't be solved because of
Chameleon nature? And the last thing - why didn't you use
QueryByAttributes layer function for this kind of searching? I suppose I
wouldn't get any speed using it...

Anyway, thank you very much


> -----Original Message-----
> From: Delfos, Jacob [mailto:jacob.delfos at maunsell.com] 
> Sent: Wednesday, April 05, 2006 12:45 AM
> To: Gambin Dejan
> Cc: chameleon at lists.maptools.org
> Subject: RE: LocateByAttribute highlighting issues
> Dejan,
> There shouldn't be any reason why it wouldn't list certain 
> valid results. Can you give an example of something you think 
> it should have listed which it didn't? (give searchstring and 
> searched value). For string fields it does a "contains" 
> check, for number fields an exact match.
> The widget doesn't do any manipulation inside a shape object. 
> In other words, it takes a shape directly from the original 
> queried layer, and copies it to a new shapefile. This should 
> not cause any corruption, unless the original shapefile is 
> corrupt (import from CAD?).
> The performance is not optimal, though I found it acceptable 
> for 'normal' shapefiles. On our server (P4, 3.2GHz) it takes 
> 2 seconds to search through 70,000 records (from button press 
> until returned results page). That's worst case scenario (no 
> result, so searched all records). It can help to decrease the 
> "maxnumresults" variable, as it will stop when this value is 
> reached (e.g. will stop immediately for unique results, where 
> maxnumresults set to 1). Search time would be halved on average.
> The search is a simple sequential search, so in order to 
> optimise it you would have to alphabetically order your data 
> and rewrite the algorithm to use a binary search. I don't 
> have plans for this yet..
> Bear in mind that Internet Explorer can act up sometimes. For 
> some inexplicable reason, IE can take ~30 seconds to display 
> a result that would normally take 1 second. It's as if the 
> IFRAME is stuck. I do not know why, nor how to fix it (it's a 
> browser issue, never happens in Firefox). 
> Regards,
> Jacob
> > -----Original Message-----
> > From: Gambin Dejan [mailto:Dejan.Gambin at pula.hr]
> > Sent: 4 April 2006 21:43
> > To: Delfos, Jacob
> > Cc: chameleon at lists.maptools.org
> > Subject: LocateByAttribute highlighting issues
> > 
> > Hi,
> > 
> > I have some highlighting issues on LocateByAttribute 
> widget. I have a 
> > line shapefile (roads). The widget finds the attributes, 
> lists them in 
> > a table, but:
> > 
> > 1. There are some results in a table which the widget doesn't
> > highlight.
> > I suppose you can tell me what can be the reason? Maybe some 
> > parameters
> > that you set when you create the queryresultshapefile...(by 
> the way I
> > looked into this shapefile and it is OK)...
> > 
> > 2. Sometimes, the line is not completely highlighted, only 
> some points 
> > on the line are "yellowed", not the whole line (this happens with 
> > lines that have less "nodes")
> > 
> > One more question - is there a way to increase the search 
> performance? 
> > It is pretty slow sometimes. Can I index dbf file maybe? Or 
> something 
> > else?
> > 
> > 
> > thanks
> > 
> > regards, dejan
> > 

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