dates and time

src/gribmessage.cpp

@@ -102,13 +102,16 @@ using namespace std;
 
  //stringstream ss(date);
  strptime(date.c_str(), "%Y%m%d", &tm);
- //ss >> get_time(&tm, "%Y%m%d");
-
- return std::chrono::system_clock::from_time_t(std::mktime(&tm));
+ auto forecastTime = getTimeNumeric() / 100;
+ auto chronoDate = std::chrono::system_clock::from_time_t(std::mktime(&tm));
+ chronoDate += std::chrono::hours(forecastTime);
+ return chronoDate;
+
  }
 
  chrono::system_clock::time_point GribMessage::getObsDate() {
  auto dt = getChronoDate();
+
  //TODO - this is flakey but follows current logic
  //amend to use the stepUnit and not assume all steps are unit "h"
  auto hours = getStep();

tests/test_dates.py

@@ -0,0 +1,48 @@
+import polars as pl
+
+class TestLocations:
+
+ def __getLocations(self):
+ # Locations are Canary Wharf and Manchester
+ return pl.DataFrame(
+ {"lat": [51.5054, 53.4808], "lon": [-0.027176, 2.2426]}
+ ).to_arrow()
+
+ def test_with_zero_hour_run_and_hour_3(self, resource):
+ from gribtoarrow import GribReader
+
+ locations = self.__getLocations()
+
+ reader = GribReader(
+ str(resource) + "/gep01.t00z.pgrb2a.0p50.f003"
+ ).withLocations(locations)
+
+ df = pl.concat(
+ pl.from_arrow(message.getDataWithLocations()) for message in reader
+ )
+
+ date_hours = df.select(pl.col("datetime").dt.hour().unique())['datetime'].to_list()
+ forecast_hours = df.select(pl.col("forecast_date").dt.hour().unique())['forecast_date'].to_list()
+
+ assert all(x == 3 for x in date_hours)
+ assert all(x == 0 for x in forecast_hours)
+
+ def test_with_18_hour_run_and_hour_6(self, resource):
+ from gribtoarrow import GribReader
+
+ locations = self.__getLocations()
+
+ reader = GribReader(
+ str(resource) + "/ecmwfaifs0h.grib"
+ ).withLocations(locations)
+
+ df = pl.concat(
+ pl.from_arrow(message.getDataWithLocations()) for message in reader
+ )
+
+ date_hours = df.select(pl.col("datetime").dt.hour().unique())['datetime'].to_list()
+ forecast_hours = df.select(pl.col("forecast_date").dt.hour().unique())['forecast_date'].to_list()
+
+ assert all(x == 0 for x in date_hours)
+ assert all(x == 18 for x in forecast_hours)
+