zoomToEnvelope not working

Question

Example code below displays two layers and attempts to zoom to an envelope defined by a geographic lat-long box, but the zoom doesn't work.  Suspect I am missing something simple with how the envelope is defined?

Thanks ahead of time for any help.

Brian.  
  //
  // ----- OpenStreetMap base layer
  //
  AGSOpenStreetMapLayer *baseLayer = [[AGSOpenStreetMapLayer alloc] init];
  [self.mapView addMapLayer:baseLayer withName:@OpenStreetMap];
  [baseLayer release];
  //
  // ----- US highways from ESRI
  //
  NSURL* url = [NSURL URLWithString: @"http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer"];  
  AGSDynamicMapServiceLayer* highwayLayer = [AGSDynamicMapServiceLayer dynamicMapServiceLayerWithURL: url];
  [self.mapView addMapLayer:highwayLayer withName:@US Highways];
  //
  // ----- zoom to approximately Colorado
  //
  AGSSpatialReference *sr = [AGSSpatialReference spatialReferenceWithWKID:4326];
 AGSEnvelope *env = [AGSEnvelope envelopeWithXmin:-110.0 
                                              ymin:35.0 
                                              xmax:-100.0 
                                              ymax:40.0 
                                  spatialReference:sr];
  [self.mapView zoomToEnvelope:env animated:YES];

BrianKrzys · Answer

Thanks, that was it, somehow I thought it would convert the coordinates automatically to match the base map.  Working code below.

Cheers, Brian.  AGSSpatialReference *sr = [AGSSpatialReference spatialReferenceWithWKID:102100];
 AGSEnvelope *env = [AGSEnvelope envelopeWithXmin:-12158332
                                              ymin:4392194
                                              xmax:-11341332
                                              ymax:5006778
                                  spatialReference:sr];
  [self.mapView zoomToEnvelope:env animated:YES];

NimeshJarecha · Answer

It is not working because your map (self.mapView.spatialReference) is in WebMercator ( base map - AGSOpenStreetMapLayer's spatial reference) and your envelope is in wgs1984 (wkid:4326). The envelope passed in the zoomToEnvelope must be in map's spatial reference.

Hope this helps!

Regards,
Nimesh