Strange map draw issue

[Steve Hall]

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
>
>  
>


-- 
Steve Hall
Technical Consultant
Mercator GeoSystems Ltd

Tel (UK) : +44 (0) 114 235 3409
Tel (US) : +1 (562) 735 3541
Fax      : +44 (0) 114 235 3409
Mobile   : +44 (0) 771 828 6323
Email    : steve.hall at mercatorgeosystems.com
Web      : www.mercatorgeosystems.com
Skype    : mercatorgeosystems



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