getContextForPoint.m

// get Context for a point

SGContextQuery *query = [SGContextQuery queryWithPoint:[SGPoint pointWithLat:37.772445 lon:-122.405913]];

[client getContextForQuery:query
                  callback:[SGCallback callbackWithSuccessBlock:
                            ^(id response) {
                                // you've got Context!
                                // to create an SGContext object...
                                SGContext *context = [SGContext contextWithDictionary:response];
                            } failureBlock:^(NSError *error) {
                                // handle failure
                            }]];