[mapserver-users] symbol circle (ellipse) rendered not round but oval

Stephen Woodbridge woodbri at swoodbridge.com
Thu Jan 14 09:25:27 PST 2010


So if I want ten pixel ellipses with a 1, 2, or 3 pixels gap how would 
you specify that?

points 10 10 gap 1 (or 2 or 3)?

-Steve W

Havard Tveite wrote:
> If Thomas B. agrees, I think it would be reasonable to also
> open a bug on the gap calculation.
> In my opinion, since the word "gap" is used, the correct
> way to specify a symbol with ellipses that has the same
> gap between them as the diameter of the ellipses should be
> as follows:
> 
> symbol
>   name dots
>   type ellipse
>   points 1 1 end
>   gap 1
> end
> 
> or an equivalent "scaled" version such as:
> 
> symbol
>   name dots
>   type ellipse
>   points 23 23 end
>   gap 23
> end
> 
> The actual size of the ellipses (and the width of the gaps)
> should be determined by the SIZE in CLASS-> STYLE.  If
> SIZE is 10, the ellipses should have a 10 pixel diameter
> (and should have a 10 pixel gap between them).
> 
> I have been hesitant to file bugs regarding symbology, since
> the documentation on symbology is lacking and there is not
> complete agreement on how some of the things that has to do
> with symbology should work.  There have also been
> discussions on changing some behaviour and mechanisms for
> symbology.
> First we have to agree on how things should work and document
> it, then we can file bugs if behaviour is not as expected.
> 
> Håvard
> 
> Oliver Christen wrote:
>> Hi Steve
>>
>> I followed your suggestion and opened a documentation bug
>>
>> thanks
>> Oliver
>>
>>> Hi guys,
>>>
>>> I haven't followed this whole thread but I think it should be better 
>>> documented so people can understand how to use this. Please write a 
>>> doc bug and put as much information in the bug about how this works 
>>> as you have been able to discover.
>>>
>>> Thanks,
>>>   -Steve W
>>>
>>> Oliver Christen wrote:
>>>> Thank you Håvard
>>>> I see you have changed "points 1 1 end" by "points 8 8 end".
>>>> Tell me if im wrong, but these values are only used to render the 
>>>> proportions of the elipse but not it's size, is that correct?
>>>> so if I understand correctly, using larger values for the elipse 
>>>> width/height refine the rendering of the vectorised dot geometry ?
>>>>
>>>> regards
>>>> Oliver
>>>>
>>>>> Dear Oliver Christen,
>>>>>
>>>>> Using Mapserver 5.6.0 and AGG rendering, you can achieve what
>>>>> you want by using a combination of ellipse size and gap size
>>>>> in the symbol definition.
>>>>> There is something strange in the calculations (a gap of
>>>>> about half the ellipse size seems to produce touching symbols),
>>>>> so in your case, you could try to use 8 as the diameter of the
>>>>> ellipses, and 20 + 4 (half the ellipse size) = 24 as the
>>>>> gap:
>>>>>
>>>>> symbol
>>>>>  name dots
>>>>>  type ellipse
>>>>>  points 8 8 end
>>>>>  gap 24
>>>>> end
>>>>>
>>>>>
>>>>> Håvard
>>>>>
>>>>> Oliver Christen wrote:
>>>>>> thank you Thomas
>>>>>>
>>>>>> so if I have a dot of, for example, 8px and I want a space pf 20px 
>>>>>> between the dots, I need a gap of 20/8 =  2.5
>>>>>>
>>>>>> but as far as I can see, Mapserver doesnt like none-integer value 
>>>>>> for gap.
>>>>>>
>>>>>> what should I do? :(
>>>>>>
>>>>>> 2010/1/12 thomas bonfort <thomas.bonfort at gmail.com 
>>>>>> <mailto:thomas.bonfort at gmail.com>>
>>>>>>
>>>>>>     gap in pixels = symbol->gap * style->size
>>>>>>
>>>>>>
>>>>>>     On Tue, Jan 12, 2010 at 16:52, Oliver Christen
>>>>>>     <oliver.christen at camptocamp.com
>>>>>>     <mailto:oliver.christen at camptocamp.com>> wrote:
>>>>>>
>>>>>>         GAP 20 is really giving unwanted result:
>>>>>>          http://dev.camptocamp.com/~ochriste/tilecache9.png
>>>>>>         <http://dev.camptocamp.com/%7Eochriste/tilecache9.png>
>>>>>>          though using only one style instead of two seems to solve 
>>>>>> the
>>>>>>         oval problem (but why ???)
>>>>>>          style
>>>>>>              symbol "dots"
>>>>>>              size 8
>>>>>>              color 204 102 0
>>>>>>              outlinecolor  102 51 0
>>>>>>             end
>>>>>>          I dont understand how GAP is supposed working:
>>>>>>          with GAP 2, I had ~10px between dots,
>>>>>>         with GAP 3, I had ~18px between dots,
>>>>>>         with GAP 4, I had ~26px between dots
>>>>>>          whats the logic ?
>>>>>>
>>>>>>             ----- Original Message -----
>>>>>>             *From:* thomas bonfort <mailto:thomas.bonfort at gmail.com>
>>>>>>             *To:* Oliver Christen 
>>>>>> <mailto:oliver.christen at camptocamp.com>
>>>>>>             *Cc:* mapserver-users at lists.osgeo.org
>>>>>>             <mailto:mapserver-users at lists.osgeo.org>
>>>>>>             *Sent:* Tuesday, January 12, 2010 4:36 PM
>>>>>>             *Subject:* Re: [mapserver-users] symbol circle (ellipse)
>>>>>>             rendered not round but oval
>>>>>>
>>>>>>             symbol
>>>>>>              name dots
>>>>>>              type ellipse
>>>>>>              points 1 1 end
>>>>>>              gap 20
>>>>>>             end
>>>>>>
>>>>>>             ...
>>>>>>
>>>>>>             style
>>>>>>              symbol "dots"
>>>>>>              size 8
>>>>>>              color r g b
>>>>>>              outlinecolor  r g b
>>>>>>             end
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>             On Tue, Jan 12, 2010 at 16:31, Oliver Christen
>>>>>>             <oliver.christen at camptocamp.com
>>>>>>             <mailto:oliver.christen at camptocamp.com>> wrote:
>>>>>>
>>>>>>                 Hi Thomas :)
>>>>>>                  thanks for the answer, but sadely it didnt solve 
>>>>>> my problem:
>>>>>>                  here are a few tests I did:
>>>>>>                  using GAP 20 gave me really weird result:
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache6_gap_20.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache6_gap_20.png>
>>>>>>                  using PATTERN 1 22 END gave me better result, but 
>>>>>> the
>>>>>>                 dot are still slightly oval:
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache7_pattern.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache7_pattern.png>
>>>>>>                  I wondered if the visual effect may have come 
>>>>>> from the
>>>>>>                 fact im pilling up two circle one over the other, but
>>>>>>                 even when trying to display only the outer or inner
>>>>>>                 circles, the circle are still slightly off:
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache4_outercircle.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache4_outercircle.png>
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache5_innercircle.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache5_innercircle.png>
>>>>>>                 (both at once
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache3_bothcircle.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache3_bothcircle.png>)
>>>>>>                  any other idea? ^_^
>>>>>>
>>>>>>                     ----- Original Message -----
>>>>>>                     *From:* thomas bonfort
>>>>>>                     <mailto:thomas.bonfort at gmail.com>
>>>>>>                     *To:* Oliver Christen
>>>>>>                     <mailto:oliver.christen at camptocamp.com>
>>>>>>                     *Cc:* mapserver-users at lists.osgeo.org
>>>>>>                     <mailto:mapserver-users at lists.osgeo.org>
>>>>>>                     *Sent:* Tuesday, January 12, 2010 3:18 PM
>>>>>>                     *Subject:* Re: [mapserver-users] symbol circle
>>>>>>                     (ellipse) rendered not round but oval
>>>>>>
>>>>>>                     hi Oliver :)
>>>>>>
>>>>>>                     try with GAP 20 instead of STYLE 1 20 END 
>>>>>> (which is
>>>>>>                     deprecated btw, use PATTERN now)
>>>>>>
>>>>>>                     cheers,
>>>>>>                     thomas
>>>>>>
>>>>>>                     On Tue, Jan 12, 2010 at 15:04, Oliver Christen
>>>>>>                     <oliver.christen at camptocamp.com
>>>>>>                     <mailto:oliver.christen at camptocamp.com>> wrote:
>>>>>>
>>>>>>                         hello
>>>>>>
>>>>>>                         I have a weird problem with symbology.
>>>>>>                         Im rendering a line with dots, but the 
>>>>>> dots are
>>>>>>                         not round but slightly oval, see image
>>>>>>
>>>>>> http://dev.camptocamp.com/~ochriste/tilecache.png
>>>>>>
>>>>>> <http://dev.camptocamp.com/%7Eochriste/tilecache.png>
>>>>>>
>>>>>>                         Any idea what could be the cause ?
>>>>>>
>>>>>>                         Here is my symbol definition:
>>>>>>
>>>>>>                         SYMBOL
>>>>>>                          NAME "linie-gepunkt10"
>>>>>>                          TYPE ELLIPSE
>>>>>>                          POINTS
>>>>>>                           1 1
>>>>>>                          END
>>>>>>                          STYLE
>>>>>>                           1 20
>>>>>>                          END
>>>>>>                          FILLED TRUE
>>>>>>                         END
>>>>>>
>>>>>>                         and my layer's class definition:
>>>>>>
>>>>>>                          CLASS
>>>>>>                           EXPRESSION "3"
>>>>>>                           MAXSCALEDENOM 200001
>>>>>>                           STYLE
>>>>>>                             SYMBOL "linie-gepunkt10"
>>>>>>                             SIZE 10
>>>>>>                             COLOR 102 51 0
>>>>>>                           END
>>>>>>                           STYLE
>>>>>>                             SYMBOL "linie-gepunkt10"
>>>>>>                             SIZE 8
>>>>>>                             COLOR 204 102 0
>>>>>>                           END
>>>>>>                          END
>>>>>>
>>>>>>                         and the map outputformat:
>>>>>>
>>>>>>                         OUTPUTFORMAT
>>>>>>                          NAME png
>>>>>>                          DRIVER "AGG/PNG"
>>>>>>                          MIMETYPE "image/png"
>>>>>>                          IMAGEMODE RGBA
>>>>>>                          EXTENSION "png"
>>>>>>                          FORMATOPTION "INTERLACE=OFF"
>>>>>>                         END
>>>>>>                         
>>>>>> _______________________________________________
>>>>>>                         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
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> -- 
>>>>> Håvard Tveite
>>>>> Department of Mathematical Sciences and Technology, UMB
>>>>> Drøbakveien 31, POBox 5003, N-1432 Ås, NORWAY
>>>>> Phone: +47 64965483 Fax: +47 64965401 http://www.umb.no/imt/
>>>>>
>>>> _______________________________________________
>>>> mapserver-users mailing list
>>>> mapserver-users at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>
>>
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
> 




More information about the MapServer-users mailing list