[Chameleon] Drawing a Point

Ken Sanderson ken at rockies.ca
Thu Aug 12 17:23:31 EDT 2004


Thanks Paul. I found that code in one of the other widgets this morning
and had added it in to fix my CursorPos widget reliance. I ended up
scrapping it because I needed to do the conversion Pix to Geo in
Javascript as well for my function, so instead of doing it twice I just
used the GetHTMLHiddenVariables() function to setup two hidden form
variables in my widget, that I then add values to on the onmouseup
javascript function. Not sure if it's better that way, or worse, or all
the same?

Another question I had was is there any real difference between using
NAV_INPUT_COORDINATES over MAP_CURSOR_POS_X and MAP_CURSOR_POS_Y? From
what I could tell in the other widgets they actually populate the
NAV_INPUT_COORDINATES value with those two items anyways. Seems like
less javascript action to not populate NAV_INPUT_COORDINATES and then
not have to explode the results into individual coords?

Thanks,

Ken

-----Original Message-----
From: chameleon-bounces at lists.maptools.org
[mailto:chameleon-bounces at lists.maptools.org] On Behalf Of Paul Spencer
Sent: August 12, 2004 3:02 PM
To: Ken Sanderson
Cc: chameleon at lists.maptools.org
Subject: Re: [Chameleon] Drawing a Point


for the record, Ken's code works perfectly for me.  Here is the 
additional logic to remove the requirement for the cursor position
widget:

$szInputCoords = $this->getVar( "NAV_INPUT_COORDINATES" ); $aPixPos =
explode(",", $szInputCoords);

$nMinX = $this->moMapObject->oMap->extent->minx;
$nMaxX = $this->moMapObject->oMap->extent->maxx;
$nMinY = $this->moMapObject->oMap->extent->miny;
$nMaxY = $this->moMapObject->oMap->extent->maxy;
$dfGeoWidth = ($nMaxX-$nMinX);
$dfGeoHeight = ($nMaxY-$nMinY);
$dfGeoMiddleX = $nMinX + ($dfGeoWidth / 2 );
$dfGeoMiddleY = $nMinY + ($dfGeoHeight / 2 );

include_once( CHAMELEON_PATH."/widgets/geomath.php" );
$aLatLon = Pix2Georef (
     $aPixPos[0],
     $aPixPos[1],
     $dfGeoMiddleX, $dfGeoMiddleY,
     $dfGeoWidth,   $dfGeoHeight,
     $this->moMapObject->oMap->width,
     $this->moMapObject->oMap->height  );

at this point, $aLatLon[0] = lon and $aLatLon[1] = lat :)

Cheers,

Paul

Ken Sanderson wrote:

> I just let Chameleon do the drawing, as my widget triggers the submit 
> of the form. Here is my ParseURL blurb that I am using:
> 
>         if ($szCmd == "GetPoint"){
>             /** get a list of the layer names */	
>             $aszLayerNames = 
> $this->moMapNavigator->oSession->oMap->getAllLayerNames();
>             
>             /** check to see if the 'your points' layer already 
> exists. If so just use that layer,
>                 if not then create it */
>             if(in_array("Your Points", $aszLayerNames)){
>               $poLayer = 
> $this->moMapNavigator->oSession->oMap->getLayerByName("Your Points");
>               $poClass = $poLayer->getClass(0);
>               $poStyle = $poClass->getStyle(0);
>             } else {
>               /** creating the new layer which will live as long as 
> the current session */
>               $poLayer = ms_newLayerObj($this->moMapObject->oMap);
>               $poLayer->set("name", "Your Points");
>               $poLayer->set("status", MS_ON);
>               $poLayer->set("type", MS_LAYER_POINT);
>               $poLayer->set("labelcache", MS_OFF);
>               $poClass = ms_newClassObj($poLayer);
>               $poClass->set("name", "dynamic point class");
>               $poStyle = ms_newStyleObj($poClass);
>               $poStyle->set("symbolname","star");
>               $poStyle->set("size", 15);
>               $poStyle->color->setRGB(255, 0, 0);
>               $poStyle->outlinecolor->setRGB(0,0,0);
>             }
>             
>             $pt = ms_newPointObj();
>             $ln = ms_newLineObj();
>             $shp = ms_newShapeObj(MS_SHAPE_POINT);
>             
>             $theX = "";
>             $theX = $this->getVar("CursorPos_X");
>             $theY = "";
>             $theY = $this->getVar("CursorPos_Y");
>                         
>             $pt->setXY($theX,$theY); 
>             $ln->add($pt); 
>             $shp->add($ln);  
>             $poLayer->addFeature($shp);
>         }
> 
> Ken
> 
> -----Original Message-----
> From: chameleon-bounces at lists.maptools.org
> [mailto:chameleon-bounces at lists.maptools.org] On Behalf Of Ken-ichi
> Sent: August 12, 2004 11:14 AM
> To: Jason Fournier
> Cc: chameleon at lists.maptools.org
> Subject: Re: [Chameleon] Drawing a Point
> 
> 
> Thanks for the tip on the Locate widget.  Unfortunately, as far as I 
> can
> 
> tell, that works by creating a temporary shapefile, adding a point to
> the shapefile, and then setting the shapefile as the data source for
the
> 
> new layer.  I want to do something much simpler, which is simply 
> drawing
> 
> a point directly to the map with the pointObj's draw() method.  I've
> done this with MapScript before, basically with this same code.
> 
> Does anyone know if there's a better way to get at the ImageObj than
> $map->draw() in Chameleon?  I feel like that's where my problem might
> be.
> 
> -Ken-ichi
> 
> Jason Fournier wrote:
> 
> 
>>If you take a look at the Locate widget it contains a significant
>>amount of code related
>>to adding a point on the map.  If you're able to swim your way through
> 
> it you may find
> 
>>some useful tidbits.
>>
>>Perhaps someone else on the list knows offhand?
>>
>>If this fails then I'd suggest mailing the MapServer list as there are
>>many PHP/MapScript
>>(and generally more MapScript) developers who may have input.
>>
>>As for debugging ... what kind of information were you looking for?
>>Are you looking for
>>information about Chameleon errors?  This can be reported by the
> 
> ErrorReport widget.  Or
> 
>>are you interested more in logging the application?
>>
>>Thanks,
>>Jason
>>
>>
>>
>>
>>On Aug 11, Ken-ichi <kueda at wso.williams.edu> wrote:
>> 
>>
>>
>>>Hi again.  To learn about widget development, I'm trying to make a
>>>copy
>>>of the ZoomIn widget draw a point on the map instead of zooming in.
> 
> To
> 
>>>that end, I've altered the ParseURL method so that the if(
> 
> $szInputType
> 
>>>== "POINT" ) clause looks like this:
>>>
>>>           if ($szInputType == "POINT")
>>>           {
>>>               $aPixPos = explode(",", $szInputCoords);
>>>              
>>>               //draw a point with MapScript
>>>               $map = $this->moMapNavigator->oSession->oMap;
>>>
>>>               $daLayer = ms_newLayerObj($map);
>>>               $daLayer->set("type", MS_LAYER_POINT);
>>>               $daLayer->set("transform", MS_FALSE);
>>>               $daLayer->set("status", MS_ON);
>>>                     
>>>               $class = ms_newClassObj($daLayer);
>>>               $class->set("name", "Temp Class");
>>>               $style = ms_newStyleObj($class);
>>>               $style->color->setRGB(255,0,0);
>>>               $style->set("symbolname", "circle");
>>>               $style->set("size", 10);
>>>
>>>               $my_point = ms_newPointObj();
>>>               $my_point->setXY($aPixPos[0],$aPixPos[1]);
>>>                    
>>>
>>>               $image = $map->draw();
>>>                    
>>>               $temp = $my_point->draw( $map, $daLayer, $image, 0, 
>>>"Temp Point" );
>>>
>>>               if( $temp == MS_SUCCESS ) $daLayer->set("name",
> 
> $temp);
> 
>>>           }
>>>
>>>This successfully adds a layer to the legend with the correct 
>>>styling, but fails to draw the point on the map.  Note that the last 
>>>line does result in setting the name of the new layer to MS_SUCCESS 
>>>(haven't figured out how to use any of Chameleon's debugging 
>>>capabilities, if such things exist), so the draw() method thinks it's

>>>working.
>>>
>>>Can anyone tell me what I'm doing wrong?  Many thanks.
>>>
>>>-Ken-ichi
>>>_______________________________________________
>>>Chameleon mailing list
>>>Chameleon at lists.maptools.org
>>><a
>>>   
>>>
>>
>>href='http://lists.maptools.org/mailman/listinfo/chameleon'>http://lis
>>t
>>s.maptools.org/mail
>>man/listinfo/chameleon</a>
>> 
>>
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>> 
>>
> 
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-- 
  -----------------------------------------------------------------
|Paul Spencer                           pspencer at dmsolutions.ca   |
|-----------------------------------------------------------------|
|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|
  -----------------------------------------------------------------

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