topic Re: geometryService.Project() with polygons in ArcGIS JavaScript Maps SDK Questions

geometryService.Project() with polygons

MikeAdams — Wed, 24 Aug 2011 15:35:07 GMT

Does the geometryService.Project() method work with polygons? According to the documentation, it should work for any geometries, but I can only get it to work with points. When I try using it to reproject a polygon, it returns nothing.

Re: geometryService.Project() with polygons

JeffPace — Wed, 24 Aug 2011 17:21:09 GMT

Does the geometryService.Project() method work with polygons? According to the documentation, it should work for any geometries, but I can only get it to work with points. When I try using it to reproject a polygon, it returns nothing.

Yes it works with all geometry types. Please paste an email of your code. You can also try the rest service directly to make sure you are getting the syntax right.

Re: geometryService.Project() with polygons

MikeAdams — Thu, 25 Aug 2011 14:58:03 GMT

Here is a portion of the code:

{
    // Create the spatial reference objects:
    m_spref_In = new SpatialReference(4326); // GCS_WGS_1984
    m_spref_Out = new SpatialReference(102113); // WGS_1984_Web_Mercator

    shpPolygon = ac_Polygons[i_ShapeNum]

    // Create the graphic object:
    myGraphic = new Graphic();
    myGraphic.geometry = shpPolygon.toPolygon();

    geometryService.project([ myGraphic ], m_spref_Out);
}

private function projectCompleteHandler(event:GeometryServiceEvent):void
{
      /* DEBUG */
      Alert.show("#1001: event.graphics.length = " + event.graphics.length.toString());
}

The event.graphics.length is ALWAYS zero.

Re: geometryService.Project() with polygons

KellyHutchins — Thu, 25 Aug 2011 16:04:19 GMT

Starting at version 2.0 of the API the input to the project method was switched from a graphic to a geometry. In your code it looks like you are attempting to project the graphic, try this instead:
geometryService.project([ shpPolygon ], m_spref_Out);

However, it looks like you are projecting from geographic to web mercator. If so you do not need to use project. The API contains client-side utility objects that allow you to project from geographic to web mercator and vice-versa. Here's an example:

var geom = esri.geometry.geographicToWebMercator(geometryToProject);

Here is a portion of the code:

{
    // Create the spatial reference objects:
    m_spref_In = new SpatialReference(4326); // GCS_WGS_1984
    m_spref_Out = new SpatialReference(102113); // WGS_1984_Web_Mercator

    shpPolygon = ac_Polygons[i_ShapeNum]

    // Create the graphic object:
    myGraphic = new Graphic();
    myGraphic.geometry = shpPolygon.toPolygon();
   geometryService.project([ myGraphic ], m_spref_Out);

}

private function projectCompleteHandler(event:GeometryServiceEvent):void
{
      /* DEBUG */
      Alert.show("#1001: event.graphics.length = " + event.graphics.length.toString());
}

The event.graphics.length is ALWAYS zero.

Re: geometryService.Project() with polygons

MikeAdams — Thu, 25 Aug 2011 16:45:41 GMT

We are still using version 1.3 of the API. The client had been using geographicToWebMercator, but now wants to be able to use other projections in addition to Web Mercator.

Re: geometryService.Project() with polygons

KellyHutchins — Thu, 25 Aug 2011 16:58:32 GMT

I just took another look at your code and I think you are using the Flex API? If so you might want to post this question in the flex forum:

http://forums.arcgis.com/forums/18-ArcGIS-API-for-Flex

Re: geometryService.Project() with polygons

MikeAdams — Thu, 25 Aug 2011 17:21:01 GMT

Thank you -- I have reposted it in the ArcGIS API for Flex forum.