[Chameleon] tiff hang
assefa at dmsolutions.ca
Wed Dec 8 11:32:50 EST 2004
The changes are minmal : here is what I did :
line 468) :
comment the 3 lines and add the 3 additional lines :
//$url .= "&dummy=".urlencode(microtime());
$oMap = $this->moMapObject->oMap;
$img = $oMap->draw();
$url = $img->saveWebImage();
2) in MapDHTML.js : function MapLayerDivImgOnLoad
comment the line : //url = url + "&UniqId="+unique;
Please give it a try and let me know.
Paul, I think we can easily make this a configurable thing as far as
mapdhtml is concerned. I think there might be a problem though with the
new query widget that diplays the selected element (and keep the
selection persitently) but It can also be solved with few changes.
What I propose is that Ken do the tests and if it solves his problem, I
will enter an enhancement bug on this with the changes required and we
can implement it after that.
Paul Spencer wrote:
> this is very strange. Chameleon is not aware of the image formats of
> the underlying data, it just uses mapscript to do the drawing.
> Another solution to this problem may be to have the MapDHTML widget
> render the map to a file and then load the image source in the page
> rather than use drawmap.php.
> We did this for another client who was having a strange problem with
> images half loading due to some sort of firewall problem (only in IE
> I've cc'd Assefa since he was the one who sorted that out. Assefa, can
> you post the solution to getting MapDHTML to render to a file? Do you
> think we could make this a configurable parameter in the MapDHTML widget
> (like DELAYDRAW="[true|false]" or something)?
> Ken-ichi wrote:
>> Thanks Paul. I tried loading drawmap.php directly, and that usually
>> renders the map even when the Chameleon app hangs (though sometimes it
>> hangs too), so I guess drawmap.php may not actually be the culprit. I
>> made another, minimal app with just the ZoomIn, ZoomOut, Recenter, and
>> MapDHTML widgets, and it still hangs on the tiffs, so I don't think
>> it's any of my custom widgets that are mucking things up either.
>> I am really at a loss here. The strangest thing about this is that if
>> I convert the TIFF to an Erdas Imagine file (either in Erdas or with
>> gdal_translate) everything works fine. What is it about tiffs that
>> could possibly hang up Chameleon? Why would Chameleon even be aware
>> of input file format? Don't MapServer and GDAL handle that? I know
>> they're fine because a non-Chameleon phpMapScript app renders the map
>> fine, as does the CGI.
>> Paul Spencer wrote:
>>> to debug drawmap.php, you need to grab the URL from the image in the
>>> chameleon app and load it directly in your browser. You should then
>>> see any error messages or debug output directly. Often, problems
>>> with a broken map image are related to error messages (or notices)
>>> being output before the image contents, thus creating a corrupt image.
>>> If nothing shows up immediately on viewing the drawmap.php url, you
>>> can then start to add some debugging code (echo) to drawmap.php to
>>> try to discover what is going on.
>>> Ken-ichi wrote:
>>>> Hi list. A while ago I posted an issue I'd been having with
>>>> rendering TIFFs in Chameleon
>>>> but I never really resolved it. Essentially, whenever I zoom in on
>>>> a GeoTIFF so that the TIFF fills the whole map, Chameleon hangs and
>>>> never displays the map image (I just get the spinner icon
>>>> indefinitely and then a broken image icon behind it. Try zooming in
>>>> on the DRG (Test Raster) at
>>>> to see what I'm talking about. I'm fairly sure this is a Chameleon
>>>> issue, most likely with drawmap.php, because this mapfile renders
>>>> just fine via the CGI, and with a rudimentary phpMapScript app like
>>>> this one:
>>>> The DRG is a 16M GeoTIFF from the California Spatial Information
>>>> Library, so I don't think it's to blame. You can check out my php
>>>> and MapScript config at
>>>> I'm running MapServer 4.4.0, GDAL 1.2.5, and PHP 4.3.9. Can anyone
>>>> think of a reason this could be happening, or recommend a way to
>>>> troubleshoot drawmap.php?
>>>> Chameleon mailing list
>>>> Chameleon at lists.maptools.org
>> Chameleon mailing list
>> Chameleon at lists.maptools.org
Email: assefa at dmsolutions.ca
Phone: (613) 565-5056 (ext 14)
Fax: (613) 565-0925
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