{"abstract":"Svalbard points near 21 degrees east are assigned to the wrong widened zone.","category":"Map projection transforms","checks":8,"contract":"Input [lon, lat]. zone = floor((lon+180)/6)+1, with lon=180 mapped to zone 60. Exceptions: lat in [56, 64) and lon in [3, 12) is zone 32; lat in [72, 84] uses zone 31 for lon in [0, 9), 33 for [9, 21), 35 for [21, 33) and 37 for [33, 42). Band letters \"CDEFGHJKLMNPQRSTUVWX\" (no I or O) cover 8 degrees each from -80; band X also covers up to 84 inclusive. Outside [-80, 84] the band is None. Return [zone, band].","contract_signature":"x","evaluation_group":"w2-map-projection-transforms-utm-zone-band","failed_approach":"Moving the split to 20 degrees misassigns the whole [20, 21) strip to zone 35.","family":"w2-map-projection-transforms-utm-zone-band-svalbard-zone-split","id":"FA-70001","implementations":{"attempt":{"sha256":"57170f2b0ec6f06a25dddaf27a8e947d8ef9d5eaed91d9c19763ac1d629e8bda","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(x):\n    lon, lat = x\n    zone = int(math.floor((lon + 180.0) / 6.0)) + 1\n    if zone > 60:\n        zone = 60\n    if 56.0 <= lat < 64.0 and 3.0 <= lon < 12.0:\n        zone = 32\n    if 72.0 <= lat <= 84.0 and 0.0 <= lon < 42.0:\n        if lon < 9.0:\n            zone = 31\n        elif lon < 20.0:\n            zone = 33\n        elif lon < 33.0:\n            zone = 35\n        else:\n            zone = 37\n    letters = 'CDEFGHJKLMNPQRSTUVWX'\n    if lat < -80.0 or lat > 84.0:\n        band = None\n    else:\n        band = letters[min(int((lat + 80.0) // 8), 19)]\n    return [zone, band]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('control #0', [-63.1, 21.44], [20, 'Q']), ('control #1', [-175.96, 80.22], [1, 'X']), ('control #2', [115.33, 82.84], [50, 'X']), ('control #3', [-84.72, -46.68], [16, 'G']), ('control #4', [-159.4, -47.6], [4, 'G']), ('control #5', [-170.34, 33.06], [2, 'S']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])], [('control #3', [-84.72, -46.68], [16, 'G']), ('control #4', [-159.4, -47.6], [4, 'G']), ('control #5', [-170.34, 33.06], [2, 'S']), ('control #6', [-48.09, 53.12], [22, 'U']), ('control #7', [93.32, -22.41], [46, 'K']), ('control #8', [-119.29, -22.68], [11, 'K']), ('boundary #36', [21.0, 78.0], [35, 'X']), ('boundary #37', [20.5, 79.0], [33, 'X'])], [('control #6', [-48.09, 53.12], [22, 'U']), ('control #7', [93.32, -22.41], [46, 'K']), ('control #8', [-119.29, -22.68], [11, 'K']), ('control #9', [-168.15, 26.03], [2, 'R']), ('control #10', [-111.05, -54.91], [12, 'F']), ('control #11', [139.05, -8.2], [54, 'L']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])], [('control #9', [-168.15, 26.03], [2, 'R']), ('control #10', [-111.05, -54.91], [12, 'F']), ('control #11', [139.05, -8.2], [54, 'L']), ('boundary #12', [180.0, 10.0], [60, 'P']), ('boundary #13', [-180.0, -10.0], [1, 'L']), ('regression #14', [5.0, 60.0], [32, 'V']), ('boundary #36', [21.0, 78.0], [35, 'X']), ('boundary #37', [20.5, 79.0], [33, 'X'])], [('boundary #12', [180.0, 10.0], [60, 'P']), ('boundary #13', [-180.0, -10.0], [1, 'L']), ('regression #14', [5.0, 60.0], [32, 'V']), ('boundary #15', [3.0, 56.0], [32, 'V']), ('boundary #16', [2.99, 60.0], [31, 'V']), ('boundary #17', [11.99, 63.99], [32, 'V']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"acff4948841197d036dbfa9faddc2f59e08dbbb5eee5abd8fb35be1b6d977285","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(x):\n    lon, lat = x\n    zone = int(math.floor((lon + 180.0) / 6.0)) + 1\n    if zone > 60:\n        zone = 60\n    if 56.0 <= lat < 64.0 and 3.0 <= lon < 12.0:\n        zone = 32\n    if 72.0 <= lat <= 84.0 and 0.0 <= lon < 42.0:\n        if lon < 9.0:\n            zone = 31\n        elif lon <= 21.0:\n            zone = 33\n        elif lon < 33.0:\n            zone = 35\n        else:\n            zone = 37\n    letters = 'CDEFGHJKLMNPQRSTUVWX'\n    if lat < -80.0 or lat > 84.0:\n        band = None\n    else:\n        band = letters[min(int((lat + 80.0) // 8), 19)]\n    return [zone, band]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('control #0', [-63.1, 21.44], [20, 'Q']), ('control #1', [-175.96, 80.22], [1, 'X']), ('control #2', [115.33, 82.84], [50, 'X']), ('control #3', [-84.72, -46.68], [16, 'G']), ('control #4', [-159.4, -47.6], [4, 'G']), ('control #5', [-170.34, 33.06], [2, 'S']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])], [('control #3', [-84.72, -46.68], [16, 'G']), ('control #4', [-159.4, -47.6], [4, 'G']), ('control #5', [-170.34, 33.06], [2, 'S']), ('control #6', [-48.09, 53.12], [22, 'U']), ('control #7', [93.32, -22.41], [46, 'K']), ('control #8', [-119.29, -22.68], [11, 'K']), ('boundary #36', [21.0, 78.0], [35, 'X']), ('boundary #37', [20.5, 79.0], [33, 'X'])], [('control #6', [-48.09, 53.12], [22, 'U']), ('control #7', [93.32, -22.41], [46, 'K']), ('control #8', [-119.29, -22.68], [11, 'K']), ('control #9', [-168.15, 26.03], [2, 'R']), ('control #10', [-111.05, -54.91], [12, 'F']), ('control #11', [139.05, -8.2], [54, 'L']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])], [('control #9', [-168.15, 26.03], [2, 'R']), ('control #10', [-111.05, -54.91], [12, 'F']), ('control #11', [139.05, -8.2], [54, 'L']), ('boundary #12', [180.0, 10.0], [60, 'P']), ('boundary #13', [-180.0, -10.0], [1, 'L']), ('regression #14', [5.0, 60.0], [32, 'V']), ('boundary #36', [21.0, 78.0], [35, 'X']), ('boundary #37', [20.5, 79.0], [33, 'X'])], [('boundary #12', [180.0, 10.0], [60, 'P']), ('boundary #13', [-180.0, -10.0], [1, 'L']), ('regression #14', [5.0, 60.0], [32, 'V']), ('boundary #15', [3.0, 56.0], [32, 'V']), ('boundary #16', [2.99, 60.0], [31, 'V']), ('boundary #17', [11.99, 63.99], [32, 'V']), ('boundary #21', [20.9, 80.0], [33, 'X']), ('boundary #36', [21.0, 78.0], [35, 'X'])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Stipulated deterministic toy contract on a bounded input domain; results are rounded as stated and no conformance with any published standard or library is claimed. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-map-projection-transforms-utm-zone-band-svalbard-zone-split","generated_at":"2026-09-29T14:48:16.575501+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Grid references, MGRS labels and CRS selection rely on the zone and band, including the Norway and Svalbard exceptions.","root_cause":"The zone 33 range of the Svalbard exception is closed at 21, taking the zone 35 edge.","sha256":"51fb76d3db46e4c1a3b1c773d01f0e2fc2a111f411473f40ee20945121a5e926","title":"UTM zone and latitude band lookup: svalbard zone split · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.312,"exit_code":1,"observations":[{"actual":[20,"Q"],"check":"control #0","expected":[20,"Q"],"passed":true},{"actual":[1,"X"],"check":"control #1","expected":[1,"X"],"passed":true},{"actual":[50,"X"],"check":"control #2","expected":[50,"X"],"passed":true},{"actual":[16,"G"],"check":"control #3","expected":[16,"G"],"passed":true},{"actual":[4,"G"],"check":"control #4","expected":[4,"G"],"passed":true},{"actual":[2,"S"],"check":"control #5","expected":[2,"S"],"passed":true},{"actual":[35,"X"],"check":"boundary #21","expected":[33,"X"],"passed":false},{"actual":[35,"X"],"check":"boundary #36","expected":[35,"X"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"control #0\", \"actual\": [20, \"Q\"], \"expected\": [20, \"Q\"], \"passed\": true}, {\"check\": \"control #1\", \"actual\": [1, \"X\"], \"expected\": [1, \"X\"], \"passed\": true}, {\"check\": \"control #2\", \"actual\": [50, \"X\"], \"expected\": [50, \"X\"], \"passed\": true}, {\"check\": \"control #3\", \"actual\": [16, \"G\"], \"expected\": [16, \"G\"], \"passed\": true}, {\"check\": \"control #4\", \"actual\": [4, \"G\"], \"expected\": [4, \"G\"], \"passed\": true}, {\"check\": \"control #5\", \"actual\": [2, \"S\"], \"expected\": [2, \"S\"], \"passed\": true}, {\"check\": \"boundary #21\", \"actual\": [35, \"X\"], \"expected\": [33, \"X\"], \"passed\": false}, {\"check\": \"boundary #36\", \"actual\": [35, \"X\"], \"expected\": [35, \"X\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.998,"exit_code":1,"observations":[{"actual":[20,"Q"],"check":"control #0","expected":[20,"Q"],"passed":true},{"actual":[1,"X"],"check":"control #1","expected":[1,"X"],"passed":true},{"actual":[50,"X"],"check":"control #2","expected":[50,"X"],"passed":true},{"actual":[16,"G"],"check":"control #3","expected":[16,"G"],"passed":true},{"actual":[4,"G"],"check":"control #4","expected":[4,"G"],"passed":true},{"actual":[2,"S"],"check":"control #5","expected":[2,"S"],"passed":true},{"actual":[33,"X"],"check":"boundary #21","expected":[33,"X"],"passed":true},{"actual":[33,"X"],"check":"boundary #36","expected":[35,"X"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"control #0\", \"actual\": [20, \"Q\"], \"expected\": [20, \"Q\"], \"passed\": true}, {\"check\": \"control #1\", \"actual\": [1, \"X\"], \"expected\": [1, \"X\"], \"passed\": true}, {\"check\": \"control #2\", \"actual\": [50, \"X\"], \"expected\": [50, \"X\"], \"passed\": true}, {\"check\": \"control #3\", \"actual\": [16, \"G\"], \"expected\": [16, \"G\"], \"passed\": true}, {\"check\": \"control #4\", \"actual\": [4, \"G\"], \"expected\": [4, \"G\"], \"passed\": true}, {\"check\": \"control #5\", \"actual\": [2, \"S\"], \"expected\": [2, \"S\"], \"passed\": true}, {\"check\": \"boundary #21\", \"actual\": [33, \"X\"], \"expected\": [33, \"X\"], \"passed\": true}, {\"check\": \"boundary #36\", \"actual\": [33, \"X\"], \"expected\": [35, \"X\"], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}