FAILURE MAP
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FA-70461 / GIS polygon topology / Open access

Bounding box topological relation: touching sides · case 01

Boxes stacked vertically are reported as overlapping.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Touching is detected only on vertical sides.

VERIFIED REPAIR

At the touching sides step restore `if a[2] == b[0] or b[2] == a[0] or a[3] == b[1] or b[3] == a[1]:`, leaving the rest of the model unchanged.

Unsuccessful approach: The patched test misses boxes touching along the bottom edge of a.

Case contract

Input [a, b], closed boxes [minx, miny, maxx, maxy] with positive width and height. Return "equals" if identical, else "disjoint" if separated with no shared point, else "contains" if a covers b (shared edges allowed), "within" if b covers a, else "touches" if the boxes share only boundary, else "overlaps".

Why this case matters

Spatial indexes and map tile filters prune candidates with envelope relations before exact geometry tests.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    a, b = x
    if a == b:
        return 'equals'
    if a[2] < b[0] or b[2] < a[0] or a[3] < b[1] or b[3] < a[1]:
        return 'disjoint'
    if a[0] <= b[0] and a[1] <= b[1] and a[2] >= b[2] and a[3] >= b[3]:
        return 'contains'
    if b[0] <= a[0] and b[1] <= a[1] and b[2] >= a[2] and b[3] >= a[3]:
        return 'within'
    if a[2] == b[0] or b[2] == a[0]:
        return 'touches'
    return 'overlaps'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('control #0', [[3, 0, 9, 4], [9, 3, 13, 11]], 'touches'), ('control #1', [[6, 3, 7, 5], [3, 1, 9, 6]], 'within'), ('control #2', [[5, 9, 6, 10], [3, 9, 10, 13]], 'within'), ('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches')], [('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches')], [('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('control #13', [[5, 3, 9, 9], [7, 8, 8, 15]], 'overlaps'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #16', [[0, 0, 5, 5], [5, 0, 9, 5]], 'touches'), ('boundary #17', [[0, 0, 5, 5], [5, 5, 9, 9]], 'touches'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches'), ('boundary #19', [[0, 0, 10, 10], [0, 0, 5, 5]], 'contains')]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
control #0touchestouchesPassed
control #1withinwithinPassed
control #2withinwithinPassed
control #3disjointdisjointPassed
control #4overlapstouchesFailed
control #5disjointdisjointPassed
control #6disjointdisjointPassed
control #7overlapstouchesFailed

SHA-256 / 2d63f7656b5b747f5e18a8ce9fe7b96d4fb3603e37e8468c87c209e01da048b9

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    a, b = x
    if a == b:
        return 'equals'
    if a[2] < b[0] or b[2] < a[0] or a[3] < b[1] or b[3] < a[1]:
        return 'disjoint'
    if a[0] <= b[0] and a[1] <= b[1] and a[2] >= b[2] and a[3] >= b[3]:
        return 'contains'
    if b[0] <= a[0] and b[1] <= a[1] and b[2] >= a[2] and b[3] >= a[3]:
        return 'within'
    if a[2] == b[0] or b[2] == a[0] or a[3] == b[1]:
        return 'touches'
    return 'overlaps'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('control #0', [[3, 0, 9, 4], [9, 3, 13, 11]], 'touches'), ('control #1', [[6, 3, 7, 5], [3, 1, 9, 6]], 'within'), ('control #2', [[5, 9, 6, 10], [3, 9, 10, 13]], 'within'), ('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches')], [('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches')], [('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('control #13', [[5, 3, 9, 9], [7, 8, 8, 15]], 'overlaps'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #16', [[0, 0, 5, 5], [5, 0, 9, 5]], 'touches'), ('boundary #17', [[0, 0, 5, 5], [5, 5, 9, 9]], 'touches'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches'), ('boundary #19', [[0, 0, 10, 10], [0, 0, 5, 5]], 'contains')]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
control #0touchestouchesPassed
control #1withinwithinPassed
control #2withinwithinPassed
control #3disjointdisjointPassed
control #4touchestouchesPassed
control #5disjointdisjointPassed
control #6disjointdisjointPassed
control #7overlapstouchesFailed

SHA-256 / 406ffd5b41ebda1ac4997e7c18101e9c7164da35b2c2862f45fa22d8a8252e79

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    a, b = x
    if a == b:
        return 'equals'
    if a[2] < b[0] or b[2] < a[0] or a[3] < b[1] or b[3] < a[1]:
        return 'disjoint'
    if a[0] <= b[0] and a[1] <= b[1] and a[2] >= b[2] and a[3] >= b[3]:
        return 'contains'
    if b[0] <= a[0] and b[1] <= a[1] and b[2] >= a[2] and b[3] >= a[3]:
        return 'within'
    if a[2] == b[0] or b[2] == a[0] or a[3] == b[1] or b[3] == a[1]:
        return 'touches'
    return 'overlaps'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('control #0', [[3, 0, 9, 4], [9, 3, 13, 11]], 'touches'), ('control #1', [[6, 3, 7, 5], [3, 1, 9, 6]], 'within'), ('control #2', [[5, 9, 6, 10], [3, 9, 10, 13]], 'within'), ('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches')], [('control #3', [[8, 2, 9, 4], [1, 10, 4, 15]], 'disjoint'), ('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #5', [[9, 7, 16, 13], [1, 10, 7, 13]], 'disjoint'), ('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #6', [[3, 1, 4, 5], [8, 8, 12, 15]], 'disjoint'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #8', [[2, 1, 4, 2], [3, 1, 6, 4]], 'overlaps'), ('control #9', [[7, 2, 15, 6], [8, 4, 14, 11]], 'overlaps'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches')], [('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #10', [[7, 1, 10, 3], [7, 0, 14, 3]], 'within'), ('control #11', [[2, 7, 10, 9], [10, 8, 12, 13]], 'touches'), ('control #12', [[8, 9, 9, 16], [4, 4, 11, 11]], 'overlaps'), ('control #13', [[5, 3, 9, 9], [7, 8, 8, 15]], 'overlaps'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #28', [[0, 6, 5, 9], [0, 0, 5, 6]], 'touches')], [('control #4', [[1, 1, 7, 5], [4, 5, 9, 8]], 'touches'), ('control #7', [[1, 7, 6, 11], [0, 6, 7, 7]], 'touches'), ('control #14', [[3, 2, 10, 3], [8, 5, 14, 7]], 'disjoint'), ('control #15', [[3, 5, 7, 12], [9, 2, 16, 3]], 'disjoint'), ('boundary #16', [[0, 0, 5, 5], [5, 0, 9, 5]], 'touches'), ('boundary #17', [[0, 0, 5, 5], [5, 5, 9, 9]], 'touches'), ('boundary #18', [[0, 0, 5, 5], [0, 5, 5, 9]], 'touches'), ('boundary #19', [[0, 0, 10, 10], [0, 0, 5, 5]], 'contains')]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
control #0touchestouchesPassed
control #1withinwithinPassed
control #2withinwithinPassed
control #3disjointdisjointPassed
control #4touchestouchesPassed
control #5disjointdisjointPassed
control #6disjointdisjointPassed
control #7touchestouchesPassed

SHA-256 / b46227e34ea3a8926e6849d34947c976fba2b865f7b5bd7764f1fb86ee8e9ea4

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:48:21.041261+00:00.

Case digest / bc50cd070a73f395953da40b690025649c1f2896ac8cdab839e76caf921ee82b