[Chameleon] tiff hang [2]

Bart van den Eijnden bartvde at xs4all.nl
Wed Dec 8 15:24:39 EST 2004

Btw, I do have a lot of the following Mapserver error messages in my  
Apache error log using this approach:

[Wed Dec 08 21:32:54 2004] [error] [client] Wed Dec 08  
21:32:53 2004 - msRASTERLayerOpen(): General error message. Attempt to  
open a RASTER layer, but this is only supported after a raster query.\r,  
referer: http://www.vz.geodan.nl:1111/geoservices/index.phtml

And sometimes an ECW does not turn up after zoom in, i.e. I get a complete  
empty page (no client) when zooming in on this ECW.

Best regards,

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
>>>>>>> _______________________________________________
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>>>>>>> http://lists.maptools.org/mailman/listinfo/chameleon
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