[Chameleon] tiff hang
Yewondwossen Assefa
assefa at dmsolutions.ca
Wed Dec 8 16:03:05 EST 2004
Bart,
Here is what could be happening : drawmap.php used the image_type
parameter set in chamleon.xml to select the output format that will be
used (just before the rendering). Maybe there is a diffrence between
what you setup in the map file outputformat and the one which is
selected by drawmap.php. Could this explain your problem ? (Note that
$oMapSession->oMap->selectOutputFormat($szImgType) done in drawmap.php
compares first for the mimetype and then the name for all the
outputformat defined to do it's selection).
The approch of writing the map to a temporary file does not use the
selectOutputFormat.
Both approchs use the same php mapscript draw function so the output
selection seems to be the only diffrence from what I can tell.
Later,
Bart van den Eijnden wrote:
> Assefa and list,
>
> if I use this approach the 24 bit transparency problems in Internet
> Explorer (grey background) are also gone.
>
> I reported those problems in the Mapserver bugzilla:
> http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1089
>
> Is this explainable for you guys?
>
> Best regards,
> Bart
>
> On Wed, 08 Dec 2004 15:06:59 -0500, Yewondwossen Assefa
> <assefa at dmsolutions.ca> wrote:
>
>> Ken,
>>
>> Thanks for testing.
>>
>> AFAIK, the changes would only affect the Query widget if it is used
>> with the parameters HIGHLIGHTRESULTS and PERSISTENTRESULTS. Maybe
>> Paul can comment on other widgets that I may have overlooked.
>>
>> As for the drawmap.php, It does several functionnalities (every
>> thing drawn in chamelon like map, scalebar, keymap) pass trough that
>> function. The idea behind it is that if you assigning a URL to the
>> image source (http::../drawmap.php?...), the main application page
>> does not need to wait for the map to be drawn to load completly and
>> thus It is supposed to give a better "smooth" looking apps.
>>
>> Your are the 2nd person who tried this solution and reported that
>> the application was faster considerably. When using the drawmap.php
>> method, there is a time cost associated with calling the server,
>> loading the session and then drawing the map. I would have imagined
>> that this solution would improve the rendering time slightly (since
>> session loading and call to the server are cut) but I am surprised a
>> bit to know that It has considerable effect since I always thought
>> that the main bulk of the time is taken by the map drawing. I guess
>> a good profiling might give us a better understanding.
>>
>> Anyhow I entered a bug 893 on this :
>> http://www.maptools.org/bugzilla/show_bug.cgi?id=893
>>
>>
>> Later,
>>
>>
>> Ken-ichi wrote:
>>
>>> Wow, not only did that solve my problem, but it increased map
>>> rendering speed considerably, even with no TIFFs! Thanks, Assefa
>>> and Paul. Adding a flag in the widget tag to do this would be
>>> really helpful. Are there any widgets that don't work with this
>>> adjustment, i.e. can I alter our "production" copy of Chameleon and
>>> expect other Chameleon projects on the server to work ok? What
>>> exactly is the purpose of drawmap.php anyway?
>>> Thanks again.
>>> -Ken-ichi
>>> Yewondwossen Assefa wrote:
>>>
>>>> The changes are minmal : here is what I did :
>>>>
>>>> 1) MapDHTML.widget.php : in function GetJavascriptVariables
>>>> (around line 468) :
>>>> comment the 3 lines and add the 3 additional lines :
>>>>
>>>> //$url =
>>>> WEBCOMMON."/wrapper/drawmap.php?map_session_mode=$nMapSessionMode&run_query=0&".SID.$szFatalImage;
>>>> //if (!$bCWCJSAPI)
>>>> //$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.
>>>>
>>>>
>>>> Later,
>>>>
>>>>
>>>> Paul Spencer wrote:
>>>>
>>>>> Ken,
>>>>>
>>>>> 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 strangely).
>>>>>
>>>>> 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)?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Paul
>>>>>
>>>>> 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.
>>>>>>
>>>>>> Argh.
>>>>>>
>>>>>> -Ken-ichi
>>>>>>
>>>>>> Paul Spencer wrote:
>>>>>>
>>>>>>> Ken,
>>>>>>>
>>>>>>> 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.
>>>>>>>
>>>>>>> Cheers,
>>>>>>>
>>>>>>> Paul
>>>>>>>
>>>>>>> Ken-ichi wrote:
>>>>>>>
>>>>>>>> Hi list. A while ago I posted an issue I'd been having with
>>>>>>>> rendering TIFFs in Chameleon
>>>>>>>> (http://lists.maptools.org/pipermail/chameleon/2004-August/thread.html#1245),
>>>>>>>> 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
>>>>>>>>
>>>>>>>> http://fisher.cnr.berkeley.edu/vtm/data/mapbrowse/
>>>>>>>>
>>>>>>>> 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:
>>>>>>>>
>>>>>>>> http://fisher.cnr.berkeley.edu/~kueda/mapscript_browse.phtml
>>>>>>>>
>>>>>>>> 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
>>>>>>>>
>>>>>>>> http://fisher.cnr.berkeley.edu/~kueda/phpinfo_mapscript.phtml
>>>>>>>>
>>>>>>>> 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?
>>>>>>>>
>>>>>>>> -Ken-ichi
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Chameleon mailing list
>>>>>>>> Chameleon at lists.maptools.org
>>>>>>>> http://lists.maptools.org/mailman/listinfo/chameleon
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>> Chameleon at lists.maptools.org
>>>>>> http://lists.maptools.org/mailman/listinfo/chameleon
>>>>>>
>>>>>
>>>>
>>>>
>>> _______________________________________________
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>>>
>>
>>
>
>
>
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Assefa Yewondwossen
Software Analyst
Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/
Phone: (613) 565-5056 (ext 14)
Fax: (613) 565-0925
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