[mapserver-users] GEOMTRANSFORM LABELPNT example

[Ian Walberg]

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] On Behalf Of Brent Fraser
Sent: Sunday, December 11, 2011 1:02 PM
To: thomas bonfort
Cc: 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>  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, see http://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>
>>>   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
>>>>>
>>>>>
>>>>>
>>>>>
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