[mapserver-users] Rendering of Symbols outside map window
deduikertjes
deduikertjes at xs4all.nl
Thu Feb 18 12:09:41 PST 2016
My pull request (https://github.com/mapserver/mapserver/pull/5199)
implements a gutter in WMS mode.
It is rather unobtrusive and straightforward. I am using it in
production for quit some time now.
I could not find any side effects, but I did not try in combination with
labeling or extremely large symbols.
Maybe a nice moment to review and/ or test by Patrick?
MArco
On 17-02-16 18:01, Lime, Steve D (MNIT) wrote:
>
> My memory is lousy I guess. Expanding the search rect used based on
> style sizes and to account for the use case Thomas mentions seems
> logical to me (more efficient), that or a gutter (probably easier).
> Needs a small RFC IMHO as I’m sure there would be side effects.
>
> In terms of what might be done immediately in Patrick’s case.
>
> -I wonder if using CIRCLE shapes might work. A circle must be defined
> by a minimum bounding rectangle. That is, two points that define the
> smallest square that can contain it. These two points are the two
> opposite corners of said box. Since the which shapes function operates
> on bounding boxes it should identify any of the circles that intersect
> the map extent.
>
> -Issues like this are also handled correctly with tiling (mapcache) if
> I’m not mistaken – and you can define a metatile gutter. Maybe that
> could be used. You could set up tiling and then make arbitrary WMS
> calls against mapcache if you had to, or even just use the tiles directly.
>
> -Go the PostGIS route as suggested by Ambrogio…
>
> Steve
>
> *From:*deduikertjes [mailto:deduikertjes at xs4all.nl]
> *Sent:* Tuesday, February 16, 2016 1:44 AM
> *To:* thomas bonfort <thomas.bonfort at gmail.com>; Lime, Steve D (MNIT)
> <Steve.Lime at state.mn.us>
> *Cc:* Patrick Meis <Meis at stadt-muenster.de>;
> mapserver-users at lists.osgeo.org
> *Subject:* Re: [mapserver-users] Rendering of Symbols outside map window
>
>
> >>>That's something we may want to fix.
>
> If I remember correctly, Mapserver in tile mode draws a slightly
> larger tile and crops that one (something configurable with GUTTER or
> so). I wrote my the code in my pull request along the same principle.
> Adjusting the query extent when doing whichshapes() and account for
> the size of symbols when adjusting the clipping rectangle once the
> feature is obtained might be more efficient?
>
> But maybe this discussion shoud be done in mapserver-dev?
>
> MArco
>
> On 15-02-16 21:23, thomas bonfort wrote:
>
> Steve,
>
> IIRC, we account for the size of symbols when adjusting our
> clipping rectangle once we have obtained a feature, but we do not
> adjust the query extent when doing whichshapes(). That's something
> we may want to fix.
>
> Another use-case would also be when the DATA statement does
> something like "ST_Buffer(the_geom,...) as the geom"
>
> --
>
> thomas
>
> On 15 February 2016 at 17:44, Lime, Steve D (MNIT)
> <Steve.Lime at state.mn.us <mailto:Steve.Lime at state.mn.us>> wrote:
>
> I know. We use to account for that explicitly.
>
> ------------------------------------------------------------------------
>
> *From:*deduikertjes [deduikertjes at xs4all.nl
> <mailto:deduikertjes at xs4all.nl>]
> *Sent:* Monday, February 15, 2016 2:44 AM
> *To:* Lime, Steve D (MNIT); Patrick Meis
>
>
> *Cc:* mapserver-users at lists.osgeo.org
> <mailto:mapserver-users at lists.osgeo.org>
> *Subject:* Re: [mapserver-users] Rendering of Symbols outside
> map window
>
> Steve,
>
> I think the key part in the question is here:
>
> " and the center point of the symbol is no longer inside the
> map window".
>
> To my experience a symbol doesn't get drawn at all when the
> point which is symbolized is outside the requested extent (WMS
> mode at least).
>
> To solve that I created the mentioned pull request.
>
> Or do I miss something?
>
> MArco
>
>
> On 13-02-16 00:17, Lime, Steve D (MNIT) wrote:
>
> This should already be happening. The drawing code
> traverses a layer's class/styles to commute a selection
> and clipping rectangle that is larger than the map extent.
>
> ------------------------------------------------------------------------
>
> *From:*mapserver-users
> [mapserver-users-bounces at lists.osgeo.org
> <mailto:mapserver-users-bounces at lists.osgeo.org>] on
> behalf of mdprive [deduikertjes at xs4all.nl
> <mailto:deduikertjes at xs4all.nl>]
> *Sent:* Friday, February 12, 2016 4:15 PM
> *To:* Patrick Meis
> *Cc:* mapserver-users at lists.osgeo.org
> <mailto:mapserver-users at lists.osgeo.org>
> *Subject:* Re: [mapserver-users] Rendering of Symbols
> outside map window
>
> Hi Patrick,
>
> i've submitted a pull request for extending the map by a
> buffer and then clipping it, so that partial symbols on
> the edge get rendered as well (wms non tiled mode).
>
> maybe you can build from sources and use this patch to
> solve your problem.
>
> marco
>
> --
>
>
> Op 11 feb. 2016 om 21:54 heeft Ambrogio Foletti
> <afoletti at gmail.com <mailto:afoletti at gmail.com>> het
> volgende geschreven:
>
> Hello Patrick,
>
> if you are using PostGIS as datasource, I would solve
> the problem by integrating a st_buffer in the DATA
> element itself ;) The added bonus is that you will get
> the attribute values from a GetFeatureInfo (if
> implemented) in the whole buffer zone.
>
> If not, you can try to use tile mode, and add some
> metabuffer (see mapserver doc
> <http://mapserver.org/output/tile_mode.html>)
>
> Cheers!
>
> A. Foletti
>
> 2016-02-05 10:58 GMT+01:00 Patrick Meis
> <Meis at stadt-muenster.de <mailto:Meis at stadt-muenster.de>>:
>
> Hallo,
>
> i have stumbled on a problem.
>
> I am simulating a buffering of point-data with the
> help of symbols, which I have set to
>
> sizeunit = meters
>
> size = 760
>
> These rather big symbols disappear from my map
> when I zoom in and
>
> the center point of the symbol is no longer inside
> the map window.
>
> But a significant part of the symbol should still
> be displayed.
>
> Is there any possibility of extending the rendered
> map, so that the symbols of my points
>
> are still rendered even when they are outside my
> map window?
>
> Greetz
>
> Patrick
>
>
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