{
  "title": "NASA Figure 2 direct-raster reading audit",
  "scope": "Checks DMGB project figure readings against visible pixels in NASA/TP-2000-210387 Figure 2; it does not validate NASA's source numbers, model, or conclusions.",
  "source": "NASA/TP-2000-210387, Figure 2, printed p. 21 / PDF p. 27",
  "source_pdf_sha256": "12867527b3417f5f99a39c2bae26b663a2d297157c565ccf3f6d4a1402f41bdf",
  "data_file": "figure2-direct-raster-trace.csv",
  "data_file_sha256": "4d6fbea0f756330841d2287cbd9f107da30dac823da2bd796743d668082df3b3",
  "selection": "30 manually selected integer pixels in a frozen 300-dpi source crop; 23 clear center-pixel reads and 7 explicit ambiguities. Values are calculated from recorded pixels after selection using a least-squares fit to major axis ticks.",
  "pixel_check": "Each selected point is checked for grayscale below 100 and membership in a contiguous same-column dark-ink band. This establishes visible-ink correspondence at the chosen threshold, not unique curve identity or statistical validity.",
  "omitted_uncertainty": "Vertical bars show only the same-column thresholded ink band and horizontal bars show \u00b10.5 source pixel. Axis tick-center/calibration error, antialiasing, original stroke width, and manual selection uncertainty are not fully propagated.",
  "ambiguities": "Four crossing/crowding stations at Mach 4.50\u20135.25; two alternative adjacent bands at Mach 8; one uncertain near-baseline terminal point at Mach 9.",
  "withdrawn_result": "The earlier 23-point comparison to the approximate Site line (MAE 0.108884, RMSE 0.117331, maximum 0.167021 near Mach 7) is withdrawn as a validated discrepancy because stroke identity was not established.",
  "current_comparison": "Comparisons of traces C and D with this manual raster center trace are descriptive graph-reading differences only. They are not NASA source errors, model-error estimates, or ground truth.",
  "reproduction": "The underlying project script analyses/nasa-2000-independent-blind/raster-adjudication/trace_and_compare.py regenerates the audit data and overlay; see the project analysis report for commands and tests."
}