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Geometry Service - Project Transformations?

RyanCoodey

Is there no way to set the transformations used with the Project operation in a Geometry service? I have to project some things from NAD_27 to WGS_84 in our Silverlight application and the default transformation is not acceptable.

Thanks a lot!

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GaetanLavenu

I have the problem, I would like to be able to choose a datum transformation via Rest "Project" operation on geometry services.

RaviNarayanan

Geometry service project operation via REST does not support explictly specifying a datum for transformation. In the case when a transformation is not provided to the geometry service project method, one of the 3 default transformations will be used. Please see
http://help.arcgis.com/en/sdk/10.0/arcobjects_cpp/componenthelp/index.html#//000w00000205000000

For transformation between WGS1984 to NAD_1927, the default transformation used is:
esriSRGeoTransformation_NAD1927_To_WGS1984_4, forward and reverse, WKID = 1173

RyanCoodey

Thanks a lot for the information ravi! Maybe in the future we will be able to specify the transformation?

Thanks!

nicogis

use soap
http://resources.esri.com/help/9.3/arcgisserver/apis/soap/SOAP_Geometry_Project.htm

SamLarsen

Do you know when will this be added to the JavaScript API as an option in the Geometry Service Project method?

nicogis

in 10.1 rest you can use datum transform:
http://servicesbeta2.esri.com/arcgis/sdk/rest/project.html
in js if it's not implemented you can use esri.request:


            var g = { geometryType:"esriGeometryPoint", geometries:[wgsPt.toJson()] };
            var params = { f:"json", geometries:dojo.toJson(g), inSR:4326,
                outSR:wkidMap, transformation:atransformation, transformForward:atransformForward
            };

            var requestHandle = esri.request({
                url:"http://servicesbeta4.esri.com/arcgis/rest/services/Geometry/GeometryServer/Project",
                content:params,
                callbackParamName:"callback",
                load:dojo.hitch(dojo.mixins(this, "OnSuccessProject"))
            }, {useProxy:false});

SamLarsen

I have also created an interim solution until the API catches up:

//  Use the hosted 10.1 Beta ArcGIS Server Geometry Service
gsvc = new esri.tasks.GeometryService("http://servicesbeta4.esri.com/arcgis/rest/services/Geometry/GeometryServer");
//  create a new point from the geolocation location
var point = new esri.geometry.Point(
 location.coords.longitude, location.coords.latitude, 
 new esri.SpatialReference({
  wkid: 4326
 })
);
//  set the output spatial reference for the project method
var outSR = new esri.SpatialReference({
 wkid: 27700
});
//  tack on two parameters in the query object - these will be added to the url and will give us a more accurate transformation
gsvc._url.query = dojo.mixin(gsvc._url.query, {
 //  set the datum transformation to OSGB_1936_To_WGS_1984_Petroleum (1314)
 //  the options are listed here: http://servicesbeta2.esri.com/arcgis/sdk/rest/dattrans.html
 transformation: 1314,
 //  we are transforming backwards in this case
 //  FROM WGS84 TO OSGB36
 transformForward: false
});
//  call the geometry service project method as you would normally
gsvc.project([point], outSR, function (projectedPoints) {
 //  get the projected point
 pt = projectedPoints[0];
 //  add it to the map
 addGraphic(pt);
 //  zoom the map to the added point
 map.centerAndZoom(pt, 17);
});

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