Merge branch 'dev' into iss193_optional_and_null

CHANGELOG.md

@@ -29,6 +29,7 @@ types and units.
    1. `mast_properties`.`date_from` (Issue [#193](https://github.com/IEA-Task-43/digital_wra_data_standard/issues/193))
    1. `lidar_config`.`date_from` (Issue [#193](https://github.com/IEA-Task-43/digital_wra_data_standard/issues/193))
    1. `vertical_profiler_properties`.`date_from` (Issue [#193](https://github.com/IEA-Task-43/digital_wra_data_standard/issues/193))
+   1. `height_reference` (Issue [#202](https://github.com/IEA-Task-43/digital_wra_data_standard/issues/202))
 1. To `logger_measurement_config` object:
     1. added `logger_stated_boom_orientation_deg` (Issue [#190](https://github.com/IEA-Task-43/digital_wra_data_standard/issues/190))
 1. To `sensor_type` enum add:

schema/iea43_wra_data_model.schema.json

@@ -210,8 +210,12 @@
       ]
     },
     "height_reference": {
+      "type": [
+        "string",
+        "null"
+      ],
       "title": "Height Reference",
-      "description": "The height reference frame that is used to measure the item height. E.g. onshore this is ground level i.e. the item is 0.5 m above ground level. Offshore is a bit different as it can be 20 m above mean sea level or 20 m above lowest astronomical tide.",
+      "description": "The height reference frame that is used to measure the item height. E.g. onshore this is 'ground level' i.e. the item is 0.5 m above ground level. Offshore is a bit different as it can be 20 m above 'mean sea level' or 20 m above 'lowest astronomical tide' for a fixed structure or 20 m above 'sea level' for a floating lidar.",
       "enum": [
         "ground_level",
         "mean_sea_level",
@@ -225,7 +229,7 @@
   },
   "type": "object",
   "title": "IEA Wind Resource Assessment - Data Model",
-  "description": "This Data Model schema is a digital representation of a meteorological mast used for measureing the wind resource of a potential wind farm.",
+  "description": "This Data Model schema is a digital representation of a meteorological mast used for measuring the wind resource of a potential wind farm.",
   "properties": {
     "author": {
       "type": "string",