[Chameleon] raster hang
jacob.delfos at maunsell.com
Tue Aug 24 20:26:28 EDT 2004
It sounds a little bit like the problem I seem to have with rasters; only happening every so many times, especially when there is more image in view. I have it with ECW's and TIFF (45MB RGB). My map image fails, and the session seems to hang, because I can't submit the page, but I seem to be able to open a new session in another window without much delay. I tried changing my settings in php.ini, but it had no effect. I have 'patched' my problem by placing the OnError tag in the mapDHTMLwidget image, invoking a function when it fails, which re-loads the map image after a small delay. My diagnosis so far is that something gets ahead of itself, serving the source to the client browser, and the client browser requesting the image, before the image has begun being rendered. You will find that the URL of your mapimage is valid.
I think it happens with PHP because it's slower than, for example, mapserver. What is the size of your map image. Is it larger than average, by any chance?
From: chameleon-bounces at lists.maptools.org [mailto:chameleon-bounces at lists.maptools.org] On Behalf Of Ken-ichi
Sent: 25 August 2004 04:07
To: Chameleon at lists.maptools.org
Subject: Re: [Chameleon] raster hang
I should also mention that this problem is probably TIFF specific. It
does not occur when I use an Erdas Imagine (.img) format image of the
same area, which is also about the same file size.
> Thanks for responding, Paul. I've actually set my php.ini file to be
> very lenient on resource use for other purposes, so I doubt it's that:
> max_execution_time = 60
> max_input_time = 120
> memory_limit = 510M
> I did a little more testing and found that this also happens with
> non-Chameleon phpMapScript (the MapLab non-ROSA preview app), and with
> other GeoTIFFs, but not with the mapserv CGI or the ROSA applet. So
> I'm guessing you were right to suspect the PHP side of things. Any
> more ideas, or should I take this to a more MapScript specific list?
> Ken-ichi wrote:
>> Hi folks. I've started trying to add a GeoTIFF to my Chameleon app,
>> and it really bogs it down, sometimes to a stand still. The image
>> I'm experimenting with is a 29mb unsigned 8bit GeoTIFF created in
>> Erdas. The hangs are most frequent when the tiff occupies the whole
>> map, and when I say hang, I mean that the map just doesn't render.
>> The hangs also seem to generate an httpd process that takes up a lot
>> (>20%) of my CPU activity. The relevant portion of my map file is
>> pretty simple:
>> NAME "Test Raster"
>> TYPE RASTER
>> DATA "/path/to/data.tif"
>> STATUS DEFAULT
>> I haven't specified an outputformat, except in the MAP section, where
>> I've set it to PNG (but I've switched around and that doesn't seem to
>> make much difference). This problem does not seem to occur outside
>> of Chameleon (everything works fine in MapLab's ROSA applet), and it
>> doesn't happen every time the map is loaded (although it inevitably
>> happens if you refresh the map enough).
>> Has anyone experienced this kind of behavior before? Even better,
>> anyone have any recommendations?
>> Chameleon mailing list
>> Chameleon at lists.maptools.org
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