[Chameleon] tiff hang

[Ken-ichi]

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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>>>
>>
>
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