Opened 11 years ago

Closed 11 years ago

#2370 closed defect (wontfix)

ST_EstimatedExtent bug

Reported by: strk Owned by: pramsey
Priority: blocker Milestone: PostGIS 2.1.0
Component: postgis Version: 2.1.x
Keywords: Cc:


CREATE TABLE public.source (g GEOMETRY);
INSERT INTO public.source VALUES
 ('POINT(0 2047)'),
 ('POINT(0 0)'),
 ('POINT(2047 0)')
ANALYZE source;
SELECT ST_Extent(g) FROM source;
SELECT ST_Estimated_Extent('public', 'source', 'g');

Real extent: BOX(0 0,2047 2047) Estimated: BOX(-10.2349996566772 -10.2349996566772,2057.23510742188 2057.23510742188)

You can see it's not "just" a precision issue, but the minx and miny are off by 10 !

PostGIS 1.5 and 2.0 are immune.

The bogus one is POSTGIS="2.1.0beta3dev r11564"

Change History (9)

comment:1 by robe, 11 years ago

Owner: changed from pramsey to strk

comment:2 by strk, 11 years ago

Paul, any idea ? I haven't touched the stats code except for hushing compiler warnings…

comment:3 by darkblueb, 11 years ago

confirmed in test with

POSTGIS="2.1.0beta3dev r11494" GEOS="3.3.9dev-CAPI-1.7.9" PROJ="Rel. 4.8.0, 6 March 2012" LIBXML="2.8.0" }}}

comment:4 by darkblueb, 11 years ago

observed in

POSTGIS="2.1.0beta3 r11567" GEOS="3.4.0dev-CAPI-1.8.0 r3823" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.10.0, released 2013/04/13" LIBXML="2.8.0" LIBJSON="UNKNOWN" RASTER

comment:5 by pramsey, 11 years ago

Owner: changed from strk to pramsey

comment:6 by pramsey, 11 years ago

Here's the issue:

The thing is, removing this will open other problems, since this was added precisely because edge cases were being lost. At the end of the day, the "estimated" box is 1% larger than the sampled box, which is *itself* smaller than the *actual* box, since… it's a *sample*! The key word here is "estimated". I incline towards leaving thing as they are.

comment:7 by strk, 11 years ago

I don't think it's important for "estimated" bounding box to be larger than the actual one. It's important that it is "about the same as the actual one", based on a sample. If the sample is the whole set, I'd expect the estimated extent to also be the one of the whole set. That's how it worked up to 2.0. Do you have a case for that 1% enlargement ?

comment:8 by robe, 11 years ago

Can I push this forward? to 2.1.1 or you expecting to do something with this like SOON.

comment:9 by robe, 11 years ago

Resolution: wontfix
Status: newclosed

strk pramsey said he doesn't want to bother. Change back if YOU plan to do something about it. Why is this even marked as a blocker?

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