Restore genForeFireCase.py as a general landscape writer

TESTING.md

@@ -111,6 +111,26 @@ which is the point — it is the failing test the work in #175 has to make pass.
 Wiring it into CI belongs with the last step of that issue, once it can pass
 for the right reason.
 
+## Running the Landscape Generator Test (`test_genforefirecase.py`)
+
+Covers `tools/preprocessing/genForeFireCase.py`, which writes the NetCDF
+landscape file a simulation runs on. It builds a landscape, hands it to
+ForeFire, ignites it and steps, so it exercises the writer and the reader
+together rather than the writer alone. It also pins the field axis order,
+where the 3-D and 4-D paths were previously broken.
+
+**To run it manually**, after installing the Python package as above:
+
+```bash
+./.venv/bin/python tests/python/test_genforefirecase.py
+```
+
+It needs `numpy` and `netCDF4`, writes only into a temporary directory, and
+takes a few seconds. Without a built `pyforefire` the load-and-simulate case
+skips and the rest still run, so it is usable while iterating on the writer.
+
+The test doubles as the worked example for the tool.
+
 ## Other Tests
 
 The `tests/` directory contains other subdirectories (`mnh_*`, `runANN`) for testing specific features like coupled simulations. A main `tests/run.bash` script exists but is not currently fully validated in CI. Refer to specific subdirectories for details if needed.

docs/source/user_guide/landscape_file.rst

@@ -81,7 +81,26 @@ Generating a suitable ``landscape.nc`` file typically involves standard Geograph
     *   **Clip** the layers to your desired simulation domain boundaries.
     *   **Convert** the final processed layers into a single NetCDF file with appropriate variable names.
 
-3.  **ForeFire Helpers (Potentially):** Previous versions of ForeFire included Python helper scripts (e.g., `genForeFireCase.py`). While the status of V2 helpers is pending, tools might exist or be developed to assist in this NetCDF creation process. Consult the documentation sections on available tools once updated.
+3.  **ForeFire Helpers:** ``tools/preprocessing/genForeFireCase.py`` writes the file for you from numpy arrays, which is usually easier than assembling the NetCDF by hand:
+
+    .. code-block:: python
+
+       import numpy as np
+       from genForeFireCase import FiretoNC
+
+       FiretoNC("landscape.nc",
+                domainProperties={'SWx': 0., 'SWy': 0., 'SWz': 0.,
+                                  'Lx': 1000., 'Ly': 1000., 'Lz': 0.,
+                                  't0': 0., 'Lt': np.inf},
+                parametersProperties={'date': "2026-08-12T12:00:00Z",
+                                      'duration': 3600,
+                                      'refYear': 2026, 'refDay': 224,
+                                      'year': 2026, 'month': 8, 'day': 12},
+                fuelModelMap=fuel,        # (NY, NX) integer fuel indices
+                elevation=elevation,      # (NY, NX) metres
+                wind={"zonal": windU, "meridian": windV})
+
+    Field arrays are indexed outermost axis first: ``(NY, NX)``, or ``(NZ, NY, NX)`` and ``(NT, NZ, NY, NX)`` when they vary with height or time. Every key shown under ``parametersProperties`` is required.
 
 Loading in ForeFire
 -------------------

tests/python/test_genforefirecase.py

@@ -0,0 +1,208 @@
+"""Smoke test for tools/preprocessing/genForeFireCase.py.
+
+The landscape file is the thing standing between a new user and their first
+simulation, so this checks the whole path rather than the writer alone: build
+a landscape, hand it to ForeFire, ignite it, and step.
+
+It also pins the axis order. The 3-D and 4-D paths used to declare their
+dimensions in one order and assign in another: a 4-D field only broadcast when
+NY == NT and NX == NZ, and a 3-D field never got its NT dimension created.
+
+    python3 tests/python/test_genforefirecase.py
+
+Needs numpy, netCDF4 and a built pyforefire. Skips rather than fails when
+pyforefire is missing, so it stays runnable on a machine with no build.
+"""
+
+import os
+import sys
+import tempfile
+import traceback
+
+sys.path.insert(0, os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), "..", "..",
+    "tools", "preprocessing"))
+
+import numpy as np  # noqa: E402
+from netCDF4 import Dataset  # noqa: E402
+
+from genForeFireCase import FiretoNC, REQUIRED_PARAMETERS  # noqa: E402
+
+NX = 100
+NY = 100
+
+
+def domain_properties(nx=NX, ny=NY, resolution=10.0):
+    return {'SWx': 0., 'SWy': 0., 'SWz': 0.,
+            'Lx': nx * resolution, 'Ly': ny * resolution, 'Lz': 0.,
+            't0': 0., 'Lt': np.inf}
+
+
+def parameters_properties():
+    return {'date': "2026-08-12T12:00:00Z", 'duration': 3600,
+            'refYear': 2026, 'refDay': 224,
+            'year': 2026, 'month': 8, 'day': 12}
+
+
+def test_writes_a_loadable_landscape():
+    """The generated file loads in ForeFire, ignites and spreads."""
+    try:
+        import pyforefire
+    except ImportError:
+        return ["SKIP: pyforefire not importable"]
+
+    failures = []
+    with tempfile.TemporaryDirectory() as workdir:
+        path = os.path.join(workdir, "landscape.nc")
+
+        fuel = np.full((NY, NX), 1, dtype=np.int32)
+        elevation = np.zeros((NY, NX))
+        wind = {"zonal": np.full((NY, NX), 2.0),
+                "meridian": np.zeros((NY, NX))}
+
+        FiretoNC(path, domain_properties(), parameters_properties(),
+                 fuel, elevation=elevation, wind=wind)
+
+        with Dataset(path) as ds:
+            for name in ('fuel', 'altitude', 'windU', 'windV',
+                         'domain', 'parameters'):
+                if name not in ds.variables:
+                    failures.append("landscape is missing variable %s" % name)
+        if failures:
+            return failures
+
+        ff = pyforefire.ForeFire()
+        ff.setString("fuelsTableFile",
+                     os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                  "..", "runff", "fuels.csv"))
+        ff.setString("NetCDFfile", path)
+        ff.execute("FireDomain[sw=(0,0,0);ne=(1000,1000,0);t=0]")
+        ff.addLayer("propagation", "Rothermel", "propagationModel")
+        ff.execute("startFire[loc=(500,500,0);t=0]")
+        for _ in range(5):
+            ff.execute("step[dt=100]")
+
+        nodes = ff.execute("print[]").count("FireNode")
+        if nodes == 0:
+            failures.append("no fire nodes after stepping a loaded landscape")
+
+    return failures
+
+
+def test_four_dimensional_field():
+    """A 4-D field keeps its shape and its values.
+
+    Deliberately uses four different lengths: with NY == NT and NX == NZ the
+    old code's broadcast succeeded by accident.
+    """
+    failures = []
+    nt, nz, ny, nx = 5, 2, 3, 4
+
+    with tempfile.TemporaryDirectory() as workdir:
+        path = os.path.join(workdir, "landscape.nc")
+
+        fuel = np.full((ny, nx), 1, dtype=np.int32)
+        # Every element distinct, so a reordering cannot go unnoticed.
+        zonal = np.arange(nt * nz * ny * nx, dtype=float).reshape(
+            (nt, nz, ny, nx))
+        meridian = np.zeros((nt, nz, ny, nx))
+
+        FiretoNC(path, domain_properties(nx, ny), parameters_properties(),
+                 fuel, wind={"zonal": zonal, "meridian": meridian})
+
+        with Dataset(path) as ds:
+            got = np.array(ds.variables['windU'][:])
+
+        if got.shape != (nt, nz, ny, nx):
+            failures.append("windU has shape %s, expected %s"
+                            % (got.shape, (nt, nz, ny, nx)))
+        elif not np.array_equal(got, zonal):
+            failures.append("windU values do not match the input")
+
+    return failures
+
+
+def test_three_dimensional_field():
+    """A 3-D field gains a leading NT of 1 and keeps its values.
+
+    The old code never created the NT dimension on this path, so writing a
+    3-D field failed outright.
+    """
+    failures = []
+    nz, ny, nx = 2, 3, 4
+
+    with tempfile.TemporaryDirectory() as workdir:
+        path = os.path.join(workdir, "landscape.nc")
+
+        fuel = np.full((ny, nx), 1, dtype=np.int32)
+        zonal = np.arange(nz * ny * nx, dtype=float).reshape((nz, ny, nx))
+
+        FiretoNC(path, domain_properties(nx, ny), parameters_properties(),
+                 fuel, wind={"zonal": zonal,
+                             "meridian": np.zeros((nz, ny, nx))})
+
+        with Dataset(path) as ds:
+            got = np.array(ds.variables['windU'][:])
+
+        if got.shape != (1, nz, ny, nx):
+            failures.append("windU has shape %s, expected %s"
+                            % (got.shape, (1, nz, ny, nx)))
+        elif not np.array_equal(got[0], zonal):
+            failures.append("3-D windU values do not match the input")
+
+    return failures
+
+
+def test_missing_parameter_is_reported_before_writing():
+    """A missing key names itself, and leaves no half-written file behind."""
+    failures = []
+    incomplete = parameters_properties()
+    del incomplete['refDay']
+
+    with tempfile.TemporaryDirectory() as workdir:
+        path = os.path.join(workdir, "landscape.nc")
+        try:
+            FiretoNC(path, domain_properties(), incomplete,
+                     np.full((NY, NX), 1, dtype=np.int32))
+            failures.append("a missing parameter key did not raise")
+        except KeyError as error:
+            if 'refDay' not in str(error):
+                failures.append("the error does not name the missing key: %s"
+                                % error)
+        if os.path.exists(path):
+            failures.append("a file was written despite the missing key")
+
+    return failures
+
+
+def main():
+    tests = [test_writes_a_loadable_landscape,
+             test_four_dimensional_field,
+             test_three_dimensional_field,
+             test_missing_parameter_is_reported_before_writing]
+
+    failures = []
+    for test in tests:
+        try:
+            result = test()
+        except Exception:
+            result = ["%s raised:\n%s" % (test.__name__, traceback.format_exc())]
+        for line in result:
+            if line.startswith("SKIP:"):
+                print("%s: %s" % (test.__name__, line))
+            else:
+                failures.append("%s: %s" % (test.__name__, line))
+        if not result:
+            print("%s: ok" % test.__name__)
+
+    if failures:
+        print("\nFAILED with %d problem(s):" % len(failures))
+        for failure in failures:
+            print("  - %s" % failure)
+        return 1
+    print("\nOK")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

tools/README.md

@@ -9,7 +9,7 @@ to couple the simulation with MesoNH you should also edit the &NAM_FOREFIRE name
 
 List of preprocessing scripts:
 - ***clickImageToLocation.py*** sets the coordinates for the Init.ff file 
-- ***genForeFireCase.py*** contains routines for  addFieldToNcFile
+- ***genForeFireCase.py*** writes the **NetCDFfile** landscape (fuel, elevation, wind, flux models) from numpy arrays
 - ***genPrepIdeal.py*** creates the  .nam for mesonh ideal case ???
 - ***kmlDomain.py*** extracts kml files from a netcdf file
 - ***PGD2Init.py*** creates the **InitFile**=Init.ff in the **ForeFireDataDirectory** directory
@@ -19,16 +19,25 @@ List of preprocessing scripts:
 
 ### genForeFireCase
 
-Contains the preprocessing routine *FiretoNC*: 
-to be used in order to generate a packed data landscape data in cdf format for ForeFire.
+Lives in `preprocessing/genForeFireCase.py` and contains the preprocessing
+routine *FiretoNC*, used to generate a packed data landscape in cdf format for
+ForeFire.
+
 **Usage:** FiretoNC(filename, file name
          domainProperties, the domain extension (map matching forefire parameters SWx, SWy, SWz, Lx, Ly, Lz, t0, Lt)
-     parametersProperties, the other optional properties you may want to put in the list
+     parametersProperties, the simulation date and duration. All of date, duration, refYear, refDay, year, month and day are required
              fuelModelMap, a numpy integer array containing the indexes of fuel type
            elevation=None, a numpy real array with the elevation
                 wind=None, a map with a "zonal" and "meridian" numpy real array values
        fluxModelMap=None): a map with a ("table" and "name" ) and fMap "data" numpy int array values containing indices to the corresponding flux model
 
+Field arrays are indexed outermost axis first: `(NY, NX)`, or `(NZ, NY, NX)`
+and `(NT, NZ, NY, NX)` when they vary with height or time — the same
+convention `prealCF2Case.py` uses.
+
+`tests/python/test_genforefirecase.py` builds a landscape, loads it and runs a
+short simulation; it doubles as a worked example.
+
 
 ### PGD2Init
 

tools/preprocessing/READMEscripts.md

@@ -23,7 +23,7 @@ to couple the simulation with MesoNH you should also edit the &NAM_FOREFIRE name
 
 List of scripts:
 - ***clickImageToLocation.py *** sets the coordinates for the Init.ff file 
-- ***genForeFireCase.py*** contains routines for  addFieldToNcFile
+- ***genForeFireCase.py*** writes the **NetCDFfile** landscape (fuel, elevation, wind, flux models) from numpy arrays
 - ***genPrepIdeal.py*** creates the  .nam for mesonh ideal case ???
 - ***prealCF2Case.py*** creates the **NetCDFfile**=data.nc file in the **ForeFireDataDirectory** directory
 - ***pngs2bmap.py*** creates the burning map file **BMapFiles** starting from kml contours
@@ -35,7 +35,7 @@ Contains the preprocessing routine *FiretoNC*:
 to be used in order to generate a packed data landscape data in cdf format for ForeFire.
 Usage: FiretoNC(filename, file name
          domainProperties, the domain extension (map matching forefire parameters SWx, SWy, SWz, Lx, Ly, Lz, t0, Lt)
-     parametersProperties, the other optional properties you may want to put in the list
+     parametersProperties, the simulation date and duration. All of date, duration, refYear, refDay, year, month and day are required
              fuelModelMap, a numpy integer array containing the indexes of fuel type
            elevation=None, a numpy real array with the elevation
                 wind=None, a map with a "zonal" and "meridian" numpy real array values