MIGRATION_GUIDE.TXT

[Stephen Woodbridge]

Yewondwossen Assefa wrote:
> Stephen Woodbridge wrote:
>> OK, I could be wrong, but this might also be a regression that was 
>> introduced at some point.
>>
>> Does anyone else remember what the behavior used to be with this?
>>
>> Assefa, if you have some older versions of mapserver already loaded 
>> can you try this on them also. If the behavior is consistent, then 
>> document it. And I'll try to update my memory :)
>>
>  Oldest I have locally is Mapserver 4.8.x : the code in the function 
> seems to be the same as the one in the current svn. I will update the 
> docs (http://mapserver.gis.umn.edu/docs/reference/symbology) to reflect 
> this.

OK, this sounds good to me.
Thank you for doing the additional check.
-Steve W

>> Thanks,
>>   -Steve W.
>>
>> Yewondwossen Assefa wrote:
>>>
>>> Stephen Woodbridge wrote:
>>>> Yewondwossen Assefa wrote:
>>>>> Stephen Woodbridge wrote:
>>>>>> I think we need to clarify this point.
>>>>>>
>>>>>>> ----------------------------------------------------
>>>>>>> Styling/Symbolgy changes
>>>>>>> ----------------------------------------------------
>>>>>>> Prior to MapsServer 5.0, if a pixmap symbol was used in style on 
>>>>>>> a Line
>>>>>>> Layer, the symbol was used as a brush to draw the line. In 
>>>>>>> MapServer 5.0,
>>>>>>> it is possible to draw the pixmap symbol along the line (Note 
>>>>>>> that this
>>>>>>> was available using a true type symbol). To achieve  this, the 
>>>>>>> user needs
>>>>>>> to use the parameter GAP with it's pixmap symbol definition in 
>>>>>>> the symbol
>>>>>>> file. The GAP represents the distance between the symbols. If the 
>>>>>>> GAP is not
>>>>>>> given, the pixmap symbol will be used as a brush.
>>>>>>
>>>>>> With true type symbols you can specify negative values for GAP to 
>>>>>> cause the symbol to align with the line segment. Is this also 
>>>>>> supported for pixmap symbols? This should be made explicit in here.
>>>>>>
>>>>>
>>>>>  The pixmap symbols (and the true type symbols) always align with 
>>>>> the line segment. The negative gap should have the effect of adding 
>>>>> 180deg to the calculated angle.
>>>>> I will update the guide to reflect this.
>>>>
>>>> Assefa,
>>>>
>>>> The current behavior is that with a positive gap, the symbol will 
>>>> always point north, when the gap is negative it will align the 
>>>> symbol north with the direction of the line segment. I do not think 
>>>> we want to eliminate either of these options. For oneway arrows 
>>>> along streets, you need to know if the direction of travel is A-B or 
>>>> B-A and use a CLASS to select a flipped symbol for the other 
>>>> direction. You can not change the GAP to flip the symbol on a per 
>>>> shape basis in the mapfile.
>>>>
>>>
>>>  Steve,
>>>
>>>  I am not sure that when using a true type fonts,  a positive gap 
>>> will always make the symbol point north.  Here is a test I did with a 
>>> true type font :
>>>
>>>  SYMBOL
>>> NAME "I"
>>> TYPE
>>> TRUETYPE
>>> FONT "Arial"
>>> CHARACTER "I"
>>> ANTIALIAS TRUE
>>> GAP 15
>>> END
>>>
>>>  and the STYLE looks
>>>     STYLE
>>>         SYMBOL "I"
>>>          SIZE 15
>>>         COLOR 120 120 120
>>>      END
>>>
>>>  Attached is the a what it gives in Mapserver
>>>
>>>  Looking at the result, I interpret this as being the symbol is 
>>> aligned with the line and does not always point north. Is that correct ?
>>>
>>>> -Steve
>>>>
>>>>>
>>>>>> -Steve W
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>
> 
>