Here's a JSON sketch of possible POSTs and GETs

servicerequests.submit

{
    "open311": {
        "serviceRequest": [
        {
            "id": "",
            "status": "submitted",
            "location": "148 Lafayette St, New York, NY 10013",
            "location_type": "human_readable",
            "input_url": "http://api.nyc.gov/311/servicerequests.submit",
            "hub_url": "http://hub.open311.org/atom/",
            "request": [
            {
                "author": "John Doe",
                "author_email": "john@doe.com",
                "submit_date": "2009-11-02T21:18Z",
                "description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque mattis mauris nibh. Ut tincidunt sapien condimentum ipsum adipiscing cursus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Integer blandit vestibulum consequat. Cras feugiat sagittis magna, nec pretium justo pellentesque at. Suspendisse malesuada mauris id libero dapibus placerat. Aliquam a ante at augue tincidunt egestas non vitae dolor. Suspendisse dui felis, auctor venenatis fringilla vel, lobortis sit amet mi. Etiam mollis dictum justo, sed porttitor ante aliquet id. Donec consectetur accumsan erat quis fermentum.",
                "metadata": [
                {
                    "key1": "value1",
                    "key2": "value2"
                }
                ]
            }
            ],
            "media": [
            {
                "image": [
                {
                    "id": 324,
                    "url": "http://aws.amazon.com/345234/4addsf.jpg"
                },
                {
                    "id": 325,
                    "url": "http://aws.amazon.com/345234/5adsf.jpg"
                }
                ]
            }
            ]
        }
        ]
    }
}

servicerequests.get

{
    "open311": {
        "serviceRequest": [
        {
            "id": "54ASDadfgaF4",
            "status": "open",
            "location": "37.0625,-95.677068",
            "location_type": "WGS84",
            "input_url": "http://api.nyc.gov/311/servicerequests.submit",
            "hub_url": "http://hub.open311.org/atom/",
            "request": [
            {
                "author": "John Doe",
                "submit_date": "2009-11-02T21:18Z",
                "description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque mattis mauris nibh. Ut tincidunt sapien condimentum ipsum adipiscing cursus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Integer blandit vestibulum consequat. Cras feugiat sagittis magna, nec pretium justo pellentesque at. Suspendisse malesuada mauris id libero dapibus placerat. Aliquam a ante at augue tincidunt egestas non vitae dolor. Suspendisse dui felis, auctor venenatis fringilla vel, lobortis sit amet mi. Etiam mollis dictum justo, sed porttitor ante aliquet id. Donec consectetur accumsan erat quis fermentum.",
                "metadata": [
                {
                    "title": "Clogged storm drain",
                    "tags": "",
                    "customer_id": 234,
                    "open_date": "2009-11-03T11:18Z",
                    "jurisdiction_id": "10013.us",
                    "jurisdiction_name": "New York City 311",
                    "dependent_request_id": "65a4ds5f4",
                    "priority": 2,
                    "votes": 12,
                    "agency_id": "DEP",
                    "service_code": 54
                }
                ]
            }
            ],
            "location": [
            {
                "WGS84": "37.0625,-95.677068",
                "source": "148 Lafayette St, New York, NY 10013",
                "source_type": "human_readable",
                "metadata": [
                {
                    "address_id": 134123,
                    "location_proprietary": "foobar234235987",
                    "WGS84_accuracy": 0.23
                }
                ]
            }
            ],
            "media": [
            {
                "image": [
                {
                    "id": 324,
                    "url": "http://aws.amazon.com/345234/4addsf.jpg"
                },
                {
                    "id": 325,
                    "url": "http://aws.amazon.com/345234/5adsf.jpg"
                }
                ]
            }
            ]
        }
        ]
    }
}