[mapserver-users] symbol circle (ellipse) rendered not round
but oval
Havard Tveite
havard.tveite at umb.no
Thu Jan 14 12:48:58 EST 2010
Stephen Woodbridge wrote:
> 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)?
Yes, if the rendering behaviour had been according to my
preferences,
POINTS 10 10 END
GAP 1 (or 2 or 3)
should do it (if you had specified SIZE 10 in the STYLE).
You specify the gap, and not the centre to centre distance
between the ellipses.
But currently, this is not the behaviour.
Currently (with AGG in 5.6.0) you would have to specify:
POINTS 10 10 END
GAP 6 (or 7 or 8)
to get something close (if you specify SIZE 10 in the STYLE).
Something seems to be wrong when the GAP is close to
half the diameter specified in POINTS - some of the gaps
will be as expected, while others are larger (closer to the
actual number specified in GAP).
Håvard
>
> -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/
>>>>>>
>>>>> _______________________________________________
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>
>
--
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/
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