[Geomoose-users] strange problem with select

[James Klassen]

Parcels.map
On Jul 31, 2013 3:37 PM, "Bistrais, Bob" <Bob.Bistrais at maine.gov> wrote:

>  Which file would you adjust that tolerance in?****
>
> ** **
>
> *From:* Jim Klassen [mailto:klassen.js at gmail.com]
> *Sent:* Wednesday, July 31, 2013 1:40 PM
> *To:* Bistrais, Bob
> *Cc:* eadam at co.lincoln.or.us; geomoose-users at lists.osgeo.org
> *Subject:* Re: [Geomoose-users] strange problem with select****
>
> ** **
>
> This behavior appears to be deep into the MapServer code.****
>
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>
> select.php eventually calls mapquery.c:msQueryByShape which ends up in the
> mapsearch.c:msIntersect* calls.****
>
> ** **
>
> I suspect it has something to do with these all being edge cases rather
> than clear intersections.  The one bit I was able to see from the code is
> that setting TOLERANCE larger than 0 might help stabilize the results.
>  Otherwise it is patches to mapserver or switching the PHP to do the query
> outside of mapscript (maybe using GEOS or PostGIS directly?).****
>
> ** **
>
> On Jul 31, 2013, at 11:38 AM, Bistrais, Bob wrote:****
>
>
>
> ****
>
> Exactly the kind of thing I’m seeing.  Here’s a sample of my experience…**
> **
>
>  ****
>
> <image001.png>****
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>  ****
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>  ****
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>  ****
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> …Notice that 1077 (upper left of selected) has not selected.****
>
>  ****
>
>  ****
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>  ****
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>  ****
>
> *From:* Jim Klassen [mailto:klassen.js at gmail.com <klassen.js at gmail.com>]
> *Sent:* Wednesday, July 31, 2013 12:35 PM
> *To:* Bistrais, Bob
> *Cc:* eadam at co.lincoln.or.us; geomoose-users at lists.osgeo.org
> *Subject:* Re: [Geomoose-users] strange problem with select****
>
>  ****
>
> Although, this one puzzles me.  Parcels, 100ft, Parcels:  I would have
> thought '1025 would be selected since it touches the orange line (unless
> the parcels dataset has some topology issues.)****
>
>  ****
>
> <image002.jpg>****
>
>  ****
>
> On Jul 31, 2013, at 10:48 AM, Bistrais, Bob wrote:****
>
>
>
>
> ****
>
> Hi Eli,****
>
>  ****
>
> It appears to be random which adjacent polygons are selected. ****
>
>  ****
>
> Actually, yes, I see the same issue in the demo- try the Select Features
> tool.  Use a buffer of 20 feet or so, using features in Parcels.  Now
> select a parcel and hit Go.  You’ll see that it selects some of the
> adjacent parcels, but not all of them (at least not in my testing).  Try it
> and you’ll see what I mean.****
>
>  ****
>
> If you select just one polygon, then do the “Buffer these results”, I am
> finding it more consistent in selecting the adjacent polygons.****
>
>  ****
>
>  ****
>
> *From:* Eli Adam [mailto:eadam at co.lincoln.or.us <eadam at co.lincoln.or.us>]
> *Sent:* Wednesday, July 31, 2013 11:20 AM
> *To:* Bistrais, Bob
> *Cc:* geomoose-users at lists.osgeo.org
> *Subject:* Re: [Geomoose-users] strange problem with select****
>
>  ****
>
> Bob,
>
>
>
> ****
>
> On Tue, Jul 30, 2013 at 1:29 PM, Bistrais, Bob <Bob.Bistrais at maine.gov>
> wrote:****
>
> I am working on a GM parcel application (GM 2.6.1).  I was testing the
> buffered select service.  With no buffering (just select by mouse), it
> seems to work fine.  On the buffered select I encounter a weird problem.
>  If you select a parcel, set a buffer distance and query layer (the
> parcels), click Go- it selects only a few of the surrounding parcels.  In
> other words, if I set a buffer distance of 50 or 100 I’d expect to get all
> adjacent parcels selected, but it only selects some of the expected result.
> ****
>
>
> Is it random which ones are selected?  Is it a shift one way or the
> other?  Area you able to see this in the demo?  Are some never selected?
> Do you know if you have invalid/odd geometries or data in those areas?  If
> you have a PostGIS instance handy, you might want to load it up and run
> ST_IsValid (http://postgis.net/docs/manual-2.0/ST_IsValid.html) or
> similar functions to see if there is any pattern of this problem with
> something that might be in the data. ****
>
>  ****
>
> This isn't a lot of detail to try and figure it out.  You might be able to
> get more info from checking the requests and responses in firebug (i.e.
> perhaps it is a bad request vs. bad response vs. bad handling of a correct
> response, etc). ****
>
>  ****
>
> I hope these ideas lead to something useful.****
>
> Eli****
>
>  ****
>
>   ****
>
> The data is a shapefile, if that matters.   Although I had started
> modifying the select.php for my project, I went back to the original when I
> discovered the problem, and it’s still doing it.  Any idea what’s going on?
> ****
>
>
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>
>    ****
>
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> ** **
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