=== versions === python 3.12.0 | numpy 2.5.4 | pandas 3.1.0 | rasterio 1.5.2 | geopandas 1.2.0 | matplotlib 3.11.2 === study area and WorldCover tiles === Ireland (NUTS IE, 1:1M): bounds -10.66..-6.00 E, 51.42..55.44 N, geodesic area 69,940 km2 WorldCover 2021 v200 tiles: N51W012, N51W009, N51W006, N54W012, N54W009 === map class areas from pixel counts === 1,353,687,446 pixels inside Ireland; mapped area 69,940 km2 (nodata pixels: 0) class pixels area_km2 W 10 Tree cover 233,874,437 12,095.3 0.1729 20 Shrubland 16,894 0.9 0.0000 30 Grassland 998,316,939 51,557.0 0.7372 40 Cropland 64,800,106 3,370.2 0.0482 50 Built-up 20,380,643 1,054.7 0.0151 60 Bare / sparse 750,160 38.6 0.0006 80 Water 30,125,439 1,546.1 0.0221 90 Herbaceous wetland 5,422,828 277.4 0.0040 === LUCAS 2022 reference data === 8,597 LUCAS 2022 points in Ireland, surveyed 09 May 2022 .. 09 Feb 2023 observation type 1 (field, <= 100 m): 3,933 observation type 2 (field, > 100 m): 205 observation type 3 (photo-interpreted in the field): 161 observation type 7 (photo-interpreted in the office): 4,298 crosswalk LUCAS LC1 -> WorldCover: Tree cover <- B71 C C10 C20 C21 C22 C23 C30 C31 C32 C33 Shrubland <- B83 B84 D10 D20 Grassland <- B55 E10 E20 E30 Cropland <- B11 B12 B13 B14 B15 B16 B21 B22 B23 B32 B37 B41 B43 B51 B52 B53 B54 Bx1 F40 Built-up <- A11 A12 A13 A21 A22 A30 Bare / sparse <- F10 F20 H23 Water <- G11 G21 G30 G40 Herbaceous wetland <- H11 H12 H21 F40 bare soil on agricultural land counted as cropland: 74; B55 temporary grassland counted as grassland: 76 === LUCAS 2022 design weights from the master grid === master grid: 17,458 points on the 2 km grid in Ireland, 8,597 in the 2022 sample selection rate by 2018 photo-interpretation stratum (STR18): 1 arable 3,649 of 4,146 (88%) 2 permanent crops 11 of 11 (100%) 3 grass 1,903 of 6,898 (28%) 4 wooded 1,094 of 2,753 (40%) 5 shrubs 830 of 2,083 (40%) 6 bare/rare vegetation 365 of 504 (72%) 7 artificial 341 of 600 (57%) 8 inland water 335 of 368 (91%) 9 transitional/coastal water 0 of 23 (0%) 10 impossible to PI 69 of 72 (96%) design cells (NUTS 2 x STR18): 30; weights 1.00 .. 6.03; sum of weights 17,435 = grid points represented (x 4 km2 = 69,740 km2) grid points in cells with no sample (not represented): 23 === map labels at the LUCAS points === points used: 8,597 (dropped 0 with map nodata or no design weight) points whose 3x3 pixel block is all one class: 86.5% === sample confusion matrix (counts; rows = map, columns = reference) === Tree cover Shrubland Grassland Cropland Built-up Bare / sparse Water Herbaceous wetland Tree cover 711 149 262 15 105 10 19 3 Shrubland 0 1 0 0 0 0 0 0 Grassland 178 932 4344 130 197 48 20 273 Cropland 2 2 101 575 10 1 0 0 Built-up 0 2 9 0 107 7 0 0 Bare / sparse 0 0 1 0 5 4 1 0 Water 1 1 1 0 1 9 305 5 Herbaceous wetland 0 7 21 0 1 2 3 16 naive overall accuracy (count of agreeing points / all points): 0.705 Cohen's kappa: 0.494 (chance agreement 0.417) === area-adjusted error matrix (estimated % of Ireland; rows = map, columns = reference) === Tree cover Shrubland Grassland Cropland Built-up Bare / sparse Water Herbaceous wetland Tree cover 9.97 2.10 3.46 0.16 1.31 0.09 0.15 0.05 Shrubland 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Grassland 2.42 14.12 49.12 1.22 2.23 0.44 0.17 4.00 Cropland 0.01 0.02 0.81 3.89 0.08 0.01 0.00 0.00 Built-up 0.00 0.02 0.16 0.00 1.24 0.09 0.00 0.00 Bare / sparse 0.00 0.00 0.01 0.00 0.03 0.02 0.00 0.00 Water 0.03 0.02 0.01 0.00 0.01 0.07 2.04 0.04 Herbaceous wetland 0.00 0.05 0.20 0.00 0.01 0.01 0.02 0.12 class n n_eff UA_naive UA UA_ci PA_naive PA PA_ci map_km2 adj_km2 adj_ci_km2 boot_ci_km2 unweighted_km2 Tree cover 1274 989 0.558 0.576 0.031 0.797 0.803 0.027 12,095 8,687 463 438 8,264 Shrubland 1 1 1.000 1.000 0.000 0.001 0.000 0.000 1 11,417 654 607 9,335 Grassland 6122 4329 0.710 0.666 0.014 0.917 0.914 0.008 51,557 37,597 797 761 39,764 Cropland 691 448 0.832 0.808 0.036 0.799 0.739 0.043 3,370 3,687 242 225 4,042 Built-up 125 104 0.856 0.823 0.074 0.251 0.253 0.030 1,055 3,430 342 276 3,635 Bare / sparse 11 9 0.364 0.292 0.311 0.049 0.022 0.024 39 506 144 121 631 Water 323 270 0.944 0.923 0.032 0.876 0.854 0.054 1,546 1,671 115 103 1,829 Herbaceous wetland 50 44 0.320 0.294 0.137 0.054 0.028 0.013 277 2,946 353 337 2,440 overall accuracy (area-weighted, design-weighted): 0.664 +/- 0.012 (bootstrap +/- 0.011); ignoring the design weights: 0.695; naive count-based: 0.705 Pontius & Millones: quantity disagreement 0.248, allocation disagreement 0.088 (total 0.336); kappa on the area-adjusted matrix 0.419 note: map shrubland has n = 1 point, so its user's accuracy is not estimable === sensitivity: observation type, homogeneity and the Copernicus module === group subset OA n Observation type Field, <= 100 m 0.719 3933 Observation type Field, > 100 m 0.808 205 Observation type PI in the field 0.750 161 Observation type PI in the office 0.604 4298 3x3 map window All 9 pixels agree 0.699 7433 3x3 map window Mixed 0.489 1164 Copernicus module Same cover >= 20 m all round 0.778 1041 Copernicus module Same cover < 20 m 0.639 1624 survey year: 2022 7,159, 2023 1,438 points (WorldCover 2021 describes 2021) map cropland, LUCAS grassland: 101 points, of which B55 temporary grassland 25 LUCAS peat bog (H12) points by map class: Grassland 257, Herbaceous wetland 15, Water 2, Tree cover 1 === sample size for a new stratified random sample of the map === planning user's accuracies: Tree cover 0.58, Shrubland 0.50, Grassland 0.67, Cropland 0.81, Built-up 0.82, Bare / sparse 0.50, Water 0.92, Herbaceous wetland 0.50 Cochran (1977) eq. 5.25 with target SE(OA) = 0.01: n = 2171 Proportional n = 2174: SE(OA) 0.0100; SE(UA) Tree 0.026, Shrubland 0.500, Grassland 0.012, Cropland 0.039, Built-up 0.067, Bare 0.500, Water 0.039, Herbaceous 0.177 Equal n = 2168: SE(OA) 0.0218; SE(UA) Tree 0.030, Shrubland 0.030, Grassland 0.029, Cropland 0.024, Built-up 0.023, Bare 0.030, Water 0.016, Herbaceous 0.030 Compromise (min 100) n = 2171: SE(OA) 0.0113; SE(UA) Tree 0.027, Shrubland 0.050, Grassland 0.014, Cropland 0.030, Built-up 0.038, Bare 0.050, Water 0.027, Herbaceous 0.050 compromise allocation: Tree cover 347, Shrubland 100, Grassland 1155, Cropland 169, Built-up 100, Bare / sparse 100, Water 100, Herbaceous wetland 100 wrote 2,171 stratified random sample points to output/worldcover_ireland_validation_sample.gpkg map_class Grassland 1155 Tree cover 347 Cropland 169 Bare / sparse 100 Water 100 Built-up 100 Shrubland 100 Herbaceous wetland 100 === figures === wrote 6 figures to output/