[mapserver-users] GEOMTRANSFORM LABELPNT example

Brent Fraser bfraser at geoanalytic.com
Sun Dec 11 16:10:52 PST 2011


Ian,

   Using the "standard" capabilities of a POINT layer wouldn't work?

Best Regards,
Brent Fraser


On 12/11/2011 3:06 PM, Ian Walberg wrote:
>
> Brent,
>
> Ok, we had been using an earlier version of the mapserver 
> documentation we had downloaded which had the text below.
>
> The latest version now describes the discussed functionally more closely.
>
> We had been looking at using the previous functionally to draw and 
> rotate a symbol around the label text. Not what we are thinking but 
> this could be used for something like displaying the wind speed and 
> symbol rotated for the wind direction using a symbol around the outside.
>
> To do this it sounds like a new GEOMTRANSFORM type.
>
> Thanks
>
> Ian
>
> STYLE The start of a STYLE object.
>
> Label specific mechanisms of the STYLE object are the GEOMTRANSFORM 
> options:
>
> GEOMTRANSFORM [labelpnt|labelpoly] Creates geometries that can be used 
> for styling the label.
>
> . labelpnt generates a point with its center at the middle of the 
> bounding rectangle of the text.
>
> . labelpoly generates the bounding rectangle for the text, with 1 
> pixel of padding added in all directions.
>
> The resulting geometries can be styled using the mechanisms available 
> in the STYLE object.
>
> New in version 6.0.
>
> *From:*Brent Fraser [mailto:bfraser at geoanalytic.com]
> *Sent:* Sunday, December 11, 2011 1:52 PM
> *To:* Ian Walberg
> *Cc:* mapserver-users at lists.osgeo.org
> *Subject:* Re: [mapserver-users] GEOMTRANSFORM LABELPNT example
>
> Ian,
>
>   No, there is no ability to do that, unless you use POSITION CC.  
> There had been some discussion several months ago to add functions to 
> the GEOMTRANSFORM resulting in RFC 72 
> (http://www.mapserver.org/development/rfc/ms-rfc-72.html)
>
> I think something like
>
> GEOMTRANSFORM (getCentroid(labelpoly))
>
> would be a good addition, but I don't have a specific use-case.  What 
> were you planning to do the center of the label polygon?
>
> Best Regards,
> Brent Fraser
>
>
> On 12/11/2011 2:18 PM, Ian Walberg wrote:
>
> So is it expected that labelpnt generates a point with its center at the middle of the bounding rectangle of the text?
>   
> Thanks
>   
> Ian
>   
>   
> -----Original Message-----
> From:mapserver-users-bounces at lists.osgeo.org  <mailto:mapserver-users-bounces at lists.osgeo.org>  [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Brent Fraser
> Sent: Sunday, December 11, 2011 1:02 PM
> To: thomas bonfort
> Cc:mapserver-users at lists.osgeo.org  <mailto:mapserver-users at lists.osgeo.org>
> Subject: Re: [mapserver-users] GEOMTRANSFORM LABELPNT example
>   
> Thomas,
>   
>    I tracked it down to the LABELCACHE setting.
>   
> LABELCACHE ON  gives the expected results LABELCACHE OFF  gives my old blue-dot-on-the-left results.
>   
> See attached PDFs.
>   
> Best Regards,
> Brent Fraser
>   
>   
> On 12/11/2011 1:05 PM, thomas bonfort wrote:
>
>     There might have been a bug in the initial implementation. trying it
>
>     out with current trunk gives me the expected result, unless I'm
>
>     missing something.
>
>       
>
>       
>
>     On Sun, Dec 11, 2011 at 20:44, Brent Fraser<bfraser at geoanalytic.com>  <mailto:bfraser at geoanalytic.com>   wrote:
>
>         Thomas,
>
>            See comments below.
>
>           
>
>         Best Regards,
>
>         Brent Fraser
>
>           
>
>           
>
>           
>
>         On 12/11/2011 12:26 PM, thomas bonfort wrote:
>
>             I think this is all expected behavior, although the documentation
>
>             may be incorrect.
>
>               
>
>             LABELPNT draws a marker on the geographic position the label is
>
>             attached to. This corresponds to the center of the label text only
>
>             if the label is in position CC.
>
>         I think that is what is intended but my original test case (using CC
>
>         ) resulted in the LABELPNT rendered on the left side of the
>
>         labelpoly, seehttp://lists.osgeo.org/pipermail/mapserver-dev/attachments/20110526/47c9bc8c/labelpnt-0001.png.
>
>             I had expected it to be coincident with the yellow circle and green cross.
>
>           
>
>           
>
>             To draw a label at the center of the label text, another
>
>             geomtransform would have to be implemented, named e.g. LABELBBOXCENTROID.
>
>         or maybe
>
>           
>
>         GEOMTRANSFORM (centroid([LABELPOLY]))
>
>           
>
>           
>
>             regards,
>
>             thomas
>
>               
>
>             On Sun, Dec 11, 2011 at 19:34, Brent Fraser<bfraser at geoanalytic.com>  <mailto:bfraser at geoanalytic.com>
>
>                wrote:
>
>                 Hey Jeff,
>
>                   
>
>                    I've been looking into this too (not finished yet).  I'm using
>
>                 v6.0.1 and can reproduce my original results (blue dot to the left)
>
>                 AND Ian's (grey dot coincident with white dot).  Very strange.  My
>
>                 shapefile dataset gets reprojected from geographic to UTM, so that
>
>                 may be causing the difference.
>
>                    I need to look into that...
>
>                   
>
>                 Best Regards,
>
>                 Brent Fraser
>
>                   
>
>                   
>
>                   
>
>                 On 12/11/2011 10:57 AM, Jeff McKenna wrote:
>
>                     On 11-12-11 11:20 AM, Ian Walberg wrote:
>
>                         Here is the map file we are using ms4w 3.0.3.
>
>                           
>
>                         We thought the larger grey circle should be drawn in the center
>
>                         of the label text.
>
>                           
>
>                         What have we done wrong?
>
>                           
>
>                           
>
>                     I have done some testing on this on Windows, with MapServer trunk
>
>                     (6.1-dev), here are my findings:
>
>                       
>
>                     - I used Brent's original example styles (from
>
>                       
>
>                     http://osgeo-org.1803224.n2.nabble.com/GEOMTRANSFORM-labelpnt-location-td6408065.html)
>
>                     with Ian's FEATURE layer -->     Brent's "Blue Dot" LABELPNT with POSITION
>
>                     CC is
>
>                     now correctly placed in the center of the label text (so it seems
>
>                     this has been fixed in the code, but I can't find the ticket that
>
>                     says that)
>
>                     - If I change to POSITION LR (as in Ian's example layer) then I
>
>                     get Ian's issue (LABELPNT is placed at the geometry location, not
>
>                     in the center of the label text
>
>                     - but this is now an issue of understanding the developer's logic
>
>                     (from that thread SteveL says "Let me ponder this and get back to
>
>                     you. I think it makes sense to use the label point geotransform
>
>                     only with position CC so that it matches actual shape location.")
>
>                       
>
>                     That's all I know at this point (ha pun).
>
>                       
>
>                     -jeff
>
>                       
>
>                       
>
>                       
>
>                       
>
>                 _______________________________________________
>
>                 mapserver-users mailing list
>
>                 mapserver-users at lists.osgeo.org  <mailto:mapserver-users at lists.osgeo.org>
>
>                 http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>           
>
>
>
>
>         _______________________________________________
>
>         mapserver-users mailing list
>
>         mapserver-users at lists.osgeo.org  <mailto:mapserver-users at lists.osgeo.org>
>
>         http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20111211/114f2228/attachment.htm>


More information about the MapServer-users mailing list