Strange map draw issue

[Stephen Woodbridge]

Steve,

How is your server/mapscript/etc configured. It sounds like you could 
possibly getting mapscript thread corruption or something similar to that.

-Steve W

Steve Hall wrote:
> Sorry Ed, I must have forgotten to put that part in my email.
> 
> Yes, a simple refresh of the same map will, 9 times ot of 10, get rid of 
> the garbage.  But then at a random interval it will reappear (but will 
> be different garbage).
> 
> It's kind of hard for me to "post" the entire app, or allow access, 
> right now i'm afraid so I appreciate it may be hard for anyone to help, 
> I as just fishing for ideas really!
> 
> Thanks,
> 
> 
> Steve
> 
> 
> Ed McNierney wrote:
> 
>> Steve -
>>  
>> I actually was asking if the output changed if the SAME map was 
>> refreshed - don't zoom in, out, or pan, just refresh the image/reload 
>> the page.  Does the same image request always return the same image?
>>  
>>     - Ed
>>
>> Ed McNierney
>> President and Chief Mapmaker
>> TopoZone.com / Maps a la carte, Inc.
>> 73 Princeton Street, Suite 305
>> North Chelmsford, MA  01863
>> ed at topozone.com
>> (978) 251-4242
>>
>>
>> ------------------------------------------------------------------------
>> *From:* Steve Hall [mailto:steve.hall at mercatorgeosystems.co.uk]
>> *Sent:* Thursday, September 14, 2006 10:39 AM
>> *To:* Ed McNierney
>> *Cc:* MAPSERVER-USERS at LISTS.UMN.EDU
>> *Subject:* Re: [UMN_MAPSERVER-USERS] Strange map draw issue
>>
>> Hi Ed,
>>
>> Thanks for this.  I may check my label columns in the database for 
>> NULLs and replace them with an empty string ('') instead.   It looks 
>> like a classic 'null' issue doesn't it?
>>
>> Yup - zoom in, zoom out, pan etc and the garbage generally just 
>> disappears, or changes its 'content'.   Often the angle is the same 
>> (suspicious) but sometimes not.....  There aren't any features on the 
>> angles so i'm not sure if it's a labelling issue or not.  Plus the 
>> problem only occurs about 1 in 20 or so map draws so is kind of hard 
>> to get a definite problem case.
>>
>> Checkout these additional ones :
>>
>> http://demo.mercatorgeosystems.co.uk/tmp/1158243616324003.png
>>
>> And just to prove it's not all CA....  ;-)
>>
>> http://demo.mercatorgeosystems.co.uk/tmp/1158244089248601.png
>> http://demo.mercatorgeosystems.co.uk/tmp/1158244147717403.png
>>
>> Thanks Ed,
>> Steve
>>
>>
>> Take a
>> Ed McNierney wrote:
>>
>>> Steve -
>>>  
>>> Well, just about anything in California is a little odd.....
>>>  
>>> Are you saying that if you simply refresh the image and re-draw the 
>>> exact same map you'll see this line of text change?  That's 
>>> puzzling.  I would speculate that it's a (garbage) text label for 
>>> some garbage feature - there's some feature that's defective in both 
>>> location and label (attributes messed up) and that feature is being 
>>> labeled.
>>>  
>>> The first thing I'd try is to eliminate layers from the image, 
>>> testing until the garbage goes away.  That could identify the 
>>> offending layer; if there are multiple classes in that layer, use the 
>>> same system to identify which class it is.  Then see if that says 
>>> anything helpful.
>>>  
>>>     - Ed
>>>
>>> Ed McNierney
>>> President and Chief Mapmaker
>>> TopoZone.com / Maps a la carte, Inc.
>>> 73 Princeton Street, Suite 305
>>> North Chelmsford, MA  01863
>>> ed at topozone.com
>>> (978) 251-4242
>>>
>>>
>>> ------------------------------------------------------------------------
>>> *From:* UMN MapServer Users List 
>>> [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] *On Behalf Of *Steve Hall
>>> *Sent:* Thursday, September 14, 2006 9:22 AM
>>> *To:* MAPSERVER-USERS at LISTS.UMN.EDU
>>> *Subject:* [UMN_MAPSERVER-USERS] Strange map draw issue
>>>
>>> Hi All,
>>>
>>> I've been using Mapserver for a while now, in a variety of 
>>> situations, but am seeing a slightly strange behaviour in one of my 
>>> setups.  Basically i'm getting a line of 'garbage' being drawn across 
>>> the generated map image.
>>>
>>> A sample of what I mean is here :
>>>
>>> http://demo.mercatorgeosystems.co.uk/tmp/1158239461914994.png
>>>
>>> There is no road feature or other line that should be there, and if I 
>>> redraw the map the line of garbage will either disappear or change in 
>>> either length or 'content'.  It doesn't appear all the time, but 
>>> certainly enough to be annoying.
>>>
>>> My MapServer version is 4.8.1, running with Apache 1.3.31 on Fedora 
>>> Core 4.  I've got several other MapServer based configurations on 
>>> this setup and they're all working fine.   The data source in 
>>> question is an Oracle 10g (10.1) database which is also used for 
>>> other systems and seems fine.....
>>>
>>> Weird eh?  Any suggestions much appreciated!
>>>
>>> Thanks,
>>> Steve H
>>>