How to fetch hourly observations from GeoJson endpoint?

WOW exposes observation data from various endpoints with different data types. One of them is GeoJson, which is defined as below in GeoJson.org:

GeoJSON is a format for encoding a variety of geographic data structures.GeoJSON supports the following geometry types: Point, LineString, Polygon, MultiPoint, MultiLineString, and MultiPolygon. Geometric objects with additional properties are Feature objects. Sets of features are contained by FeatureCollection objects.

WOW itself uses GeoJson format on its map from the same endpoint, so you will have the same results in the API response with the data on map. To learn how to connect to WOW API in detail, please refer to our article “How to connect to WOW API?”.

The GeoJson endpoint always shows the data in hourly ranges. It searches for the observations within that hour and shows the latest observations per site within the hour. If a site has multiple observations in that selected hour, only the latest one is returned.

You can also send parameters to filter the data or show additional information. The full list is at GetObservationsAsGeoJson API Reference, so you can tweak your result set however you wish.

Following code is a sample to access public observation data within the last hour.

private static async Task MainAsync()
{
    var observations = await GetLastHourObservationsAsGeoJson("your-api-key");
    foreach (var observation in observations.features)
    {
        Console.WriteLine("Id: " + observation.properties.reportId);
        Console.WriteLine("SiteId: " + observation.properties.msi);
        Console.WriteLine("Report Date: " + observation.properties.reportEndDateTime);
        Console.WriteLine("Temperature: " + observation.properties.primary.dt);
    }
}

private static async Task<dynamic> GetLastHourObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Common Usage Scenarios

Below, you will find a few common scenarios and their code samples.

Observations within the current hour:

private static async Task<dynamic> GetObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?timePointSlider=25"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Observations at a specific date and time:

private static async Task<dynamic> GetObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?useSlider=false&mapTime=23/04/2016 13:59"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Observations in a geographical bounding box within the past hour:

private static async Task<dynamic> GetObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?northLat=90&westLon=-180&southLat=-90&eastLon=180"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Only official observations within the past hour:

private static async Task<dynamic> GetObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?showOfficialData=on&showWowData=off"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Only WOW observations within the past hour:

private static async Task<dynamic> GetObservationsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?showOfficialData=off&showWowData=on"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Images submitted today:

private static async Task<dynamic> GetImagesAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?useSlider=false&timePointPicker=-1&mapLayer=imageKey"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Impacts submitted in the last month:

private static async Task<dynamic> GetImpactsAsGeoJson(string subscriptionKey)
{
    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://apimgmt.www.wow.metoffice.gov.uk");
        httpClient.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
        using (var response = await httpClient.GetAsync("/api/observations/geojson?useSlider=false&timePointPicker=-31&mapLayer=impactv2"))
        {
            response.EnsureSuccessStatusCode();
            return JObject.Parse(await response.Content.ReadAsStringAsync());
        }
    }
}

Observation result set format

Please See GeoJson Schema