[mapserver-users] Corrupt image output

[Tamas Szekeres]

Mike,

It's quite difficult to find out what's going on. You should file a
ticket including the example and sample data. Probably the problem may
be reproduced in other machines as well.

Best regards,

Tamas



2008/8/19 Mike Leahy <mgleahy at alumni.uwaterloo.ca>:
> Tamas,
>
> I just gave this a try a few times - deleted the cache, and loaded one tile.
>  It seems to happen less frequently, but I still have about a 1 in 3 chance
> of getting various rectangle artifacts on the image.  It basically looks
> like something forgets to draw one or more of the rgb colours.
>
> Mike
>
> Tamas Szekeres wrote:
>>
>> Mike,
>>
>> Did you experience the same problem when calling tile.php directly
>> when rendering an individual tile?
>>
>> Best regards,
>>
>> Tamas
>>
>>
>> 2008/8/19 Mike Leahy <mgleahy at alumni.uwaterloo.ca>:
>>>
>>> Hello list,
>>>
>>> I'm wondering if anyone can help me figure out a problem I'm having with
>>> corrupted output from from a tiled geotiff dataset I'm using in a ka-Map
>>> environment.  You can see what's happening to the imagery here:
>>> http://img527.imageshack.us/my.php?image=corrupthd1.png
>>>
>>> This generally happens when I'm zoomed in fairly close, and usually with
>>> this high-resolution image dataset.  However, I can get corrupted output
>>> for
>>> other raster datasets (all geotiff, but not always tiled).  It seems to
>>> happen when the machine is processing most intensively (i.e., usually
>>> when
>>> the imagery is being rendered by ka-Map).  It also seems to be limited to
>>> the laptop I am using, which is running F7-x86_64.  In contrast, I have
>>> an
>>> actual server (F8-x86_64), which has a virtually identical setup (with
>>> respect to MapServer and its various dependencies), but with lots more
>>> cpu
>>> cores and ram, and it's having no trouble at all (as far as I have
>>> noticed).
>>>
>>> The corruption in the output from the same application my laptop is not
>>> always the same - if I clear the cache for ka-Map and re-render the
>>> images,
>>> I'll get similar artifacts appearing in the output (red, green, blue
>>> and/or
>>> black rectangles), but they will vary in size and location.  It happens
>>> for
>>> both GD/AGG drivers, and JPEG/PNG output formats.
>>>
>>> Until now, I figured it was just a problem with limited memory on my
>>> laptop
>>> (it was always around 100% when rendering this imagery on the web service
>>> +
>>> viewing the application in a browser), but now I've upgraded the ram -
>>> there's plenty of spare room and I'm still getting the same problem.  I
>>> just
>>> finished upgrading Gdal from 1.5.0 to 1.5.2, and that didn't help any.
>>>
>>> Basically, the only real differences I can think of between my laptop and
>>> my
>>> server are the number of cpu cores (1 on my laptop vs. 8 on the server),
>>> and
>>> possibly the versions of some of the underlying libraries in the system.
>>>  Does anyone know where I should start looking to find the cause of this?
>>>  Or perhaps somebody recognizes this problem, and knows what I might be
>>> doing wrong...
>>>
>>> Thanks for any suggestions,
>>> Mike
>>>
>>> _______________________________________________
>>> mapserver-users mailing list
>>> mapserver-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>
>>
>