[mapserver-users] symbol circle (ellipse) rendered not round
but oval
Havard Tveite
havard.tveite at umb.no
Fri Jan 15 03:05:15 EST 2010
I think it is very important that there is a strong
relationship between the size of the symbols and the
spacing between the symbols. That makes scalable
patterned symbols possible. So I am happy with the
current (intended) behaviour.
What is needed is good documentation with examples. I
think that there is work in progress on changing some of
the mechanisms for symbology in Mapserver. When this
work has been "finalised" I will be more than willing
to contribute to the documentation.
Håvard
Oliver Christen wrote:
> mmm, in my opinion it would be clearer if the GAP didnt depend from
> anything, set the GAP to 10 would make you a spacing of 10px between each
> symbols border, whatever the values of the symbol POINTS.
> but that may be a change too important ?
>
> Oliver
>
>> 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/
>>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> mapserver-users mailing list
>>>>>>> mapserver-users at lists.osgeo.org
>>>>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>>> _______________________________________________
>>>>> mapserver-users mailing list
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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/
>>
>
>
--
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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