[ka-Map-users] Bug in label rendering

Paul Spencer pspencer at dmsolutions.ca
Tue Nov 21 19:58:34 EST 2006 

Loïc,

I'm not sure what to tell you.  Mapserver doesn't support tile  
rendering very well and the techniques that ka-Map uses are work- 
arounds for mapserver's limitations in this respect.  The default  
settings were derived from lots of trial and error and seemed to work  
in most situations.

The best advice I can offer right now is for you to try the mapserver  
mailing list since this is really a mapserver problem and I (for one)  
don't have a lot of time to spend on this right now.  Or start  
changing things and try to see the differences and see if you can  
tweak the settings to get the right effect.

Cheers (and good luck)

Paul



On 21-Nov-06, at 3:29 AM, Loïc MAZE wrote:

> Hi all,
>
> Sorry about that, but is there any news about this problem? It is  
> important for me and I have searched a solution several days but I  
> have found no way to fix it. For the moment the best solution I  
> have found is to have small symbols so if they are truncated it  
> isn't too visible. But it isn't a real solution. I can send you my  
> mapfile and my shapefiles if you want to reproduce this bug. Must I  
> also create a bug report?
>
> Regards,
> Loïc
>
>
> ----- Original Message ----- From: "Loïc MAZE" <lm at geosphere.fr>
> To: "Paul Spencer" <pspencer at dmsolutions.ca>
> Cc: "Mailing de Ka-Map" <ka-map-users at lists.maptools.org>
> Sent: Thursday, November 16, 2006 2:23 PM
> Subject: Re: [ka-Map-users] Bug in label rendering
>
>
>> Hy Paul,
>>
>> Thanks for your advice. Unfortunately, I have already played with  
>> the $metaBuffer var and have no result. I have tried many  
>> combinations by changing the $metaBuffer var (config.php) and the  
>> $tileBuffer var (tile_nocache.php). If the value of the  
>> $metaBuffer var is too low, labels are still duplicated; and if  
>> the value is too high, labels are often not drawn (but some of  
>> them are well drawn): http://img172.imageshack.us/img172/8778/ 
>> tile4iz1.jpg .
>>
>> Regards,
>> Loïc
>>
>>
>> ----- Original Message ----- From: "Paul Spencer"  
>> <pspencer at dmsolutions.ca>
>> To: "Loïc MAZE" <lm at geosphere.fr>
>> Cc: "Christopher Schmidt" <crschmidt at crschmidt.net>; "Mailing de  
>> Ka-Map" <ka-map-users at lists.maptools.org>
>> Sent: Thursday, November 16, 2006 12:28 PM
>> Subject: Re: [ka-Map-users] Bug in label rendering
>>
>>
>>> Try changing the value of $metaBuffer in config.php to 10.
>>>
>>> Cheers
>>>
>>> Paul
>>>
>>> On 16-Nov-06, at 5:40 AM, Loïc MAZE wrote:
>>>
>>>> I have today another problem with the label rendering function.  
>>>> It  is difficult to explain such a problem for me so please  
>>>> don't blame  me for my poor English. The most important thing is  
>>>> I must use the tile_nocache.php file to generate my tiles.
>>>>
>>>> I have added a layer in my mapfile in order to show labels of   
>>>> roads. The type of this layer is LINE. If I set the $tileBuffer  
>>>> var  to 0, all my labels are well drawn (the position of labels  
>>>> in the  mapfile must be set to the value AUTO in order to be  
>>>> drawn in a  tile. The PARTIALS value is of course, set to FALSE).
>>>>
>>>> The problem is I have also another layer with labels. The type  
>>>> of  this layer is POINT. If I keep the $tileBuffer var to 0,  
>>>> symbols  are truncated at tile boundaries but all the labels of  
>>>> this layer  are well drawn.
>>>> Here's a screenshot of the problem: http://img169.imageshack.us/  
>>>> img169/1242/tile2pz9.jpg .The blue line is the tile boundaries   
>>>> (drawn with the plugin Firebug).
>>>>
>>>> If I increase the $tileBuffer var, symbols are not truncated  
>>>> but  labels are duplicated (because the symbol is drawn on two  
>>>> tiles): http://img169.imageshack.us/img169/4369/tile1as5.jpg
>>>>
>>>> And if I increase the $tileBuffer var to a high value, the   
>>>> performance of Ka-map comes down and the labels in my road  
>>>> layer  are truncated: http://img93.imageshack.us/img93/6325/ 
>>>> tile3zb4.jpg
>>>>
>>>> I have searched a fix all the day and I have found nothing to  
>>>> do  for the moment.
>>>> Many thanks in advance.
>>>>
>>>> Regards,
>>>> Loïc
>>>>
>>>>
>>>>
>>>>
>>>> ----- Original Message ----- From: "Loïc MAZE" <lm at geosphere.fr>
>>>> To: "Loïc MAZE" <lm at geosphere.fr>; "Christopher Schmidt"  
>>>> <crschmidt at crschmidt.net>
>>>> Cc: "Mailing de Ka-Map" <ka-map-users at lists.maptools.org>
>>>> Sent: Tuesday, November 14, 2006 5:01 PM
>>>> Subject: Re: [ka-Map-users] Bug in label rendering
>>>>
>>>>
>>>>> I have increased the value of the $tileBuffer var in the  
>>>>> tile_nocache.php file and it works perfectly now. This var  
>>>>> seems  to have the same purpose as the $metaBuffer var in the  
>>>>> tile.php  file. Sorry for the warning and hope this will be  
>>>>> helpful for the  others. Maybe it will be interesting the  
>>>>> $tileBuffer var receive  the same value as the $metaBuffer var  
>>>>> (in config.php file).
>>>>>
>>>>> Regards,
>>>>> Loïc
>>>>>
>>>>>
>>>>> ----- Original Message ----- From: "Loïc MAZE" <lm at geosphere.fr>
>>>>> To: "Christopher Schmidt" <crschmidt at crschmidt.net>
>>>>> Cc: "Mailing de Ka-Map" <ka-map-users at lists.maptools.org>
>>>>> Sent: Tuesday, November 14, 2006 3:24 PM
>>>>> Subject: Re: [ka-Map-users] Bug in label rendering
>>>>>
>>>>>
>>>>>> All my label layers have "PARTIALS OFF".
>>>>>> Here's an example of the values I use in my mapfile :
>>>>>>
>>>>>> LABEL
>>>>>>        FONT "times"
>>>>>>        SIZE 14
>>>>>>        TYPE TRUETYPE
>>>>>>        BUFFER 0
>>>>>>        COLOR 0 0 0
>>>>>>        FORCE TRUE
>>>>>>        OFFSET 0 0
>>>>>>        PARTIALS OFF
>>>>>>        POSITION CC
>>>>>> END
>>>>>>
>>>>>> I have played a long time by changing those values but I have  
>>>>>> no result. I can notice that if FORCE has FALSE value, the  
>>>>>> labels  are not visible any more (with TRUE value they are  
>>>>>> truncated),  but it is probably not the problem...
>>>>>>
>>>>>> Regards,
>>>>>> Loïc
>>>>>>
>>>>>>
>>>>>> ----- Original Message ----- From: "Christopher Schmidt"  
>>>>>> <crschmidt at crschmidt.net>
>>>>>> To: "Loïc MAZE" <lm at geosphere.fr>
>>>>>> Cc: "Mailing de Ka-Map" <ka-map-users at lists.maptools.org>
>>>>>> Sent: Tuesday, November 14, 2006 3:07 PM
>>>>>> Subject: Re: [ka-Map-users] Bug in label rendering
>>>>>>
>>>>>>
>>>>>>> On Tue, Nov 14, 2006 at 02:55:46PM +0100, Loïc MAZE wrote:
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I have some troubles with the current version of Ka-map. I   
>>>>>>>> would like to draw some labels thanks to the label object  
>>>>>>>> used  by Mapserver to define a label. They are well drawn by  
>>>>>>>> Ka-Map  but they are often truncated at tile boundaries. It  
>>>>>>>> happens  when the label is too long to be contained by one  
>>>>>>>> tile. It  really seems like this bug : http:// 
>>>>>>>> bugzilla.maptools.org/ show_bug.cgi?id=1379 . It is marked  
>>>>>>>> as resolved for the 0.2  version of Ka-Map but changing the  
>>>>>>>> $metaBuffer var (in  config.php) doesn't work for me. I have  
>>>>>>>> played with the values  of the other vars contained in this  
>>>>>>>> file but I was unsuccessful.
>>>>>>>
>>>>>>> Does your mapfile have "PARTIALS OFF" on your label layers?  
>>>>>>> This is
>>>>>>> probably important: it prevents mapsever from trying to draw  
>>>>>>> off  the
>>>>>>> edge of the map. If this isn't the case, ka-Map won't draw them
>>>>>>> correctly regardless, because its edge label prevention is   
>>>>>>> simply not
>>>>>>> taken into account.
>>>>>>>
>>>>>>> I'd recommend trying that, and if it doesn't work, report back.
>>>>>>>
>>>>>>> Regards,
>>>>>>> -- 
>>>>>>> Christopher Schmidt
>>>>>>> Web Developer
>>>>>>
>>>>>> _______________________________________________
>>>>>> ka-Map-users mailing list
>>>>>> ka-Map-users at lists.maptools.org
>>>>>> http://lists.maptools.org/mailman/listinfo/ka-map-users
>>>>
>>>> _______________________________________________
>>>> ka-Map-users mailing list
>>>> ka-Map-users at lists.maptools.org
>>>> http://lists.maptools.org/mailman/listinfo/ka-map-users
>>>
>>> +-----------------------------------------------------------------+
>>> |Paul Spencer                          pspencer at dmsolutions.ca    |
>>> +-----------------------------------------------------------------+
>>> |Chief Technology Officer                                         |
>>> |DM Solutions Group Inc                http://www.dmsolutions.ca/ |
>>> +-----------------------------------------------------------------+
>>>
>>>
>>>
>>
>> _______________________________________________
>> ka-Map-users mailing list
>> ka-Map-users at lists.maptools.org
>> http://lists.maptools.org/mailman/listinfo/ka-map-users
>

+-----------------------------------------------------------------+
|Paul Spencer                          pspencer at dmsolutions.ca    |
+-----------------------------------------------------------------+
|Chief Technology Officer                                         |
|DM Solutions Group Inc                http://www.dmsolutions.ca/ |
+-----------------------------------------------------------------+

More information about the ka-Map-users mailing list