Restful Sensor and templating

Hello folks,

I 'm trying to create a restful sensor that can get the watertemprature from the Ocean. The goverment has placed some sensors in the ocean and it has an rest API. First I got problems with the result beeing longer than 256-charters. So I got the data using a dummy template. Now I’m struggling with creating sensors from the data I collected.

My configuration.yaml look like this:

  - platform: rest
    name: csensor
    resource: "https://as-weu-sandefjordsc-api.azurewebsites.net/api/watertemperaturemeasurements/8966e800000001be"
    value_template: 'ok'
    json_attributes:
        - SensorMeasurements
  - platform: template
    sensors:
      granholmen_measurment:
        value_template: '{{ state_attr("sensor.cstate", "SensorMeasurements")["Measurement"] }}'
        device_class: temperature
        entity_id: sensor.cstate
        unit_of_measurement: '°C'

The result from the csensor look like this:
image

But the temperatur sensor look like this:
image

Do anyone know how the write the value_template so I can get the attribute “measurement” as a the value of a temperature sensor?