IRIS
Intelligent Roadway Information System
Road Weather Information Systems
Road Weather Information Systems, or RWIS can sense data such as precipitation rate, road surface temperature, wind speed, etc. The NTCIP and Org-815 protocols can collect RWIS data.
JSON Data
The iris/rwis endpoint produces a JSON document containing an array of all
weather sensor objects.
| Key | Value |
|---|---|
name |
Weather sensor name |
location |
Location description |
lat |
Latitude of sensor |
lon |
Longitude of sensor |
settings |
Settings object |
sample |
Observation sample object |
sample_time |
Time stamp of observation |
Settings
This object contains sensor settings and configuration.
| Key | Value |
|---|---|
reference_elevation |
Reference elevation above mean sea level (meters) |
pressure_sensor_height |
Height relative to reference_elevation (meters) |
wind_sensor |
Array of wind sensor settings objects |
↳height |
Height relative to reference_elevation (meters) |
temperature_sensor |
Array of temperature sensor settings objects |
↳height |
Height relative to reference_elevation (meters) |
pavement_sensor |
Array of pavement sensor settings objects |
↳location |
Sensor location description |
↳pavement_type |
Pavement type description |
↳height |
Pavement height relative to reference_elevation (meters) |
↳exposure |
Rough estimate of solar energy (percent) |
↳sensor_type |
Sensor type description |
sub_surface_sensor |
Array of sub-surface settings objects |
↳location |
Sensor location description |
↳sub_surface_type |
Sub-surface type description |
↳depth |
Depth below pavement surface (meters) |
Sample
This object contains all collected observation data from the most recent polling
period. The wind_sensor, temperature_sensor, pavement_sensor and
sub_surface_sensor arrays match the order from the settings object.
| Key | Value |
|---|---|
atmospheric_pressure |
Atmospheric pressure (pascals) |
visibility |
Visibility (meters) |
visibility_situation |
Visibility situation description |
wind_sensor |
Array of wind sensor observations |
↳avg_speed |
Two minute average wind speed (m/s) |
↳avg_direction |
Two minute average wind direction † |
↳spot_speed |
Spot wind speed (m/s) |
↳spot_direction |
Spot wind direction † |
↳gust_speed |
Ten minute maximum wind gust speed (m/s) |
↳gust_direction |
Ten minute maximum wind gust direction † |
↳situation |
Wind situation description |
temperature_sensor |
Array of temperature sensor observations |
↳air_temp |
Instantaneous air temperature (℃) |
wet_bulb_temp |
Instantaneous wet-bulb temperature (℃) |
dew_point_temp |
Instantaneous dew point temperature (℃) |
max_air_temp |
Maximum 24 hour air temperature (℃) |
min_air_temp |
Minimum 24 hour air temperature (℃) |
relative_humidity |
Relative humidity (percent) |
precip_rate |
Precipitation rate (mm/hr) |
precip_1_hour |
One hour accumulated precipitation (mm) |
precip_3_hours |
Three hour accumulated precipitation (mm) |
precip_6_hours |
Six hour accumulated precipitation (mm) |
precip_12_hours |
Twelve hour accumulated precipitation (mm) |
precip_24_hours |
Twenty-four hour accumulated precipitation (mm) |
precip_situation |
Precipitation situation description |
pavement_sensor |
Array of pavement sensor observations |
↳surface_status |
Surface status description |
↳surface_temp |
Surface temperature (℃) |
↳pavement_temp |
Pavement temperature (℃) |
↳sensor_error |
Sensor error description |
↳ice_or_water_depth |
Surface ice or water depth (meters) |
↳salinity |
Salinity (ppm by weight) |
↳freeze_point |
Surface freeze point (℃) |
↳black_ice_signal |
Black ice signal description |
↳friction |
Coefficient of friction (percent) |
sub_surface_sensor |
Array of sub-surface observations |
↳temp |
Sub-surface temperature (℃) |
↳moisture |
Sub-surface moisture saturation (percent) |
↳sensor_error |
Sensor error description |
total_sun |
Sun during previous day (minutes; 0-1440) |
cloud_situation |
Cloud situation description |
solar_radiation |
Solar radiation (joules / m²) deprecated |
instantaneous_terrestrial_radiation |
Terrestrial radiation (watts / m²) |
instantaneous_solar_radiation |
Solar radiation (watts / m²) |
total_radiation |
Total from collection period (watts / m²) |
total_radiation_period |
Total radiation period (seconds) |
† Wind direction in degrees clockwise from due north.