=== versions ===
python 3.12.0 | pysheds 0.5 | numpy 2.5.4 | rasterio 1.5.2 | geopandas 1.2.0

=== study area ===
DTM box 350000-366000 E, 300000-314000 N (16 km x 14 km) | 3200 x 2800 cells at 5 m | evaluation box 13 km x 10 km

=== EA LIDAR composite DTM ===
elevation 22.5-406.7 m | gaps 0 cells (0.000%)

=== EA Flood Map for Planning: Flood Zones 2 and 3 ===
19411 polygons | by zone and source: FZ2/river 17389, FZ3/river 2022
FZ3 15.17 km2 | FZ2 polygons 3.52 km2, of which 0.00 km2 overlaps FZ3

=== OpenStreetMap rivers and the Buildwas gauge ===
River Severn 30.8 km, River Tern 10.1 km, River Roden 2.7 km, unnamed 0.5 km
Buildwas gauge on the River Severn at 364570 E, 304420 N | gauge datum 36 m AOD | typical high 3.4 m | highest recent 6.025 m (2014-02-11) | maximum on record 7.037 m (2000-11-02)

=== conditioning and flow routing (pysheds) ===
burned 8,039 river cells by 5 m | 0 unresolved interior pits | fill, resolve flats, D8 and accumulation in 11.6 s | 6.0% of cells raised by depression filling, deepest fill 82.1 m
streams draining >= 3 km2: 18,304 cells, about 92 km of channel | HAND computed in 1.3 s

=== height above nearest drainage ===
evaluation box: 5,200,000 cells, 20,946 without a HAND value (they drain off the grid before meeting a channel and count as dry)
HAND percentiles 10/25/50/75/90: 2.9 / 10.6 / 26.7 / 47.4 / 81.7 m | 0.39% of cells sit below their drainage cell (set to 0)
  Flood Zone 3           11.28 km2 | median HAND   2.2 m | 90th percentile   3.6 m
  Flood Zone 2           13.44 km2 | median HAND   2.3 m | 90th percentile   4.1 m
  outside Flood Zone 2  116.04 km2 | median HAND  29.9 m | 90th percentile  86.1 m
LIDAR water surface at Buildwas 38.06 m AOD = stage 2.06 m on the gauge
  typical high               stage 3.40 m -> 1.34 m above the LIDAR water surface
  highest recent (2014)      stage 6.03 m -> 3.96 m above the LIDAR water surface
  maximum on record (2000)   stage 7.04 m -> 4.98 m above the LIDAR water surface

=== inundation extents scored against the Flood Map for Planning ===
 stage | area km2 | FZ3 hit   FAR   CSI | FZ2 hit   FAR   CSI
  1.0m |     5.13 |    0.33  0.27  0.29 |    0.30  0.22  0.28
  2.0m |     8.09 |    0.46  0.36  0.37 |    0.43  0.29  0.36
  3.0m |    13.56 |    0.77  0.36  0.53 |    0.70  0.30  0.54
  4.0m |    17.53 |    0.95  0.39  0.59 |    0.88  0.32  0.62
  5.0m |    20.46 |    0.99  0.46  0.54 |    0.95  0.38  0.60
  6.0m |    22.65 |    1.00  0.50  0.49 |    0.97  0.43  0.56
  7.0m |    24.64 |    1.00  0.54  0.46 |    0.98  0.47  0.53
  8.0m |    26.53 |    1.00  0.58  0.42 |    0.98  0.50  0.49
 10.0m |    30.83 |    1.00  0.63  0.36 |    0.99  0.57  0.43
 12.0m |    35.38 |    1.00  0.68  0.32 |    1.00  0.62  0.38
best match to FZ3: HAND <= 3.75 m | CSI 0.59 | hit rate 0.92 | false-alarm ratio 0.38 | bias 1.48 | 16.74 km2 (reference 11.28 km2)
best match to FZ2: HAND <= 4.25 m | CSI 0.63 | hit rate 0.91 | false-alarm ratio 0.33 | bias 1.36 | 18.30 km2 (reference 13.44 km2)

=== sensitivity to the stream threshold ===
streams >=  0.5 km2:   224 km of channel | best FZ3 CSI 0.39 at HAND <= 3.25 m | false-alarm ratio 0.59
streams >=  1.0 km2:   160 km of channel | best FZ3 CSI 0.45 at HAND <= 3.50 m | false-alarm ratio 0.53
streams >=  3.0 km2:    92 km of channel | best FZ3 CSI 0.59 at HAND <= 3.75 m | false-alarm ratio 0.38
streams >= 10.0 km2:    50 km of channel | best FZ3 CSI 0.75 at HAND <= 4.25 m | false-alarm ratio 0.18

=== figures ===
saved 6 figures to C:\Users\Sean.Blaney\source\tgis-b7-3\tutorial-code\height-above-nearest-drainage-python\output