Research/Terra/ 536420
Task evidence / observed-flood-population

Compare population density between flood-affected and non-flood-affected areas in Bangladesh during August 2018

PassComputational taskUnpublished draft
Download evidence JSON ↓

The question

536420
Compare population density between flood-affected and non-flood-affected areas in Bangladesh during August 2018
Exact submitted task and declared adaptations
Compare population density between flood-affected and non-flood-affected areas in Bangladesh during August 2018

Task conventions: Use the frozen 2018 Bangladesh population raster and supplied event flood_bangladesh. Population source values are people/km2. Keep its entire original grid; no population resampling. Sample the original flood raster at each original population-cell centre by containing pixel (nearest alignment); no max/bilinear interpolation or inferred flooded fractions. GFD bands are 1 flooded (0/1), 2 duration in days, 3 clear-view count, 4 clear-view fraction, 5 permanent water (0/1). Observe a cell only if population is finite/unmasked, bands 1,3,5 are finite/unmasked, clear views >0, and permanent water=0. Observed band1=1 is flooded; observed band1=0 is non-flooded. Everything else is unknown/excluded, never non-flooded or zero population. Calculate original full geographic-cell WGS84 ellipsoidal meridian/parallel area in km2; density is counts/area and counts are density*area as appropriate. Sum original/derived population over flooded cells. For the density comparison use group population divided by group physical area, not an unweighted mean of densities. This explicitly defines affected as people in observed flooded cell centres, not proven personal impacts. The event covers only part of the country/month: report the observed-footprint result, never an exhaustive national total. The supplied Bangladesh event's footprint includes northern Bangladesh despite its Tibetan event label; inspect actual coverage. Permanent water, cloud gaps and unobserved regions do not establish absence of flooding. No current source substitutions. Internal benchmark only.



Publish a full native-grid selected-population raster: people per cell for observed flooded cells, zero for observed non-flooded cells, NoData elsewhere. Also publish classification (1 flooded, 0 non-flooded, NoData unknown) on the same grid. End with fenced JSON {count:observed flooded cell count,unknown_count:all other unobserved/excluded population-grid cells,coverage_note:string,selection:{collectionId,itemId,assetKey},classification:{collectionId,itemId,assetKey},metrics:{selected_people:number,nonflood_people:number,selected_area_km2:number,nonflood_area_km2:number,selected_density:number,nonflood_density:number}}. Label classification unit as dimensionless and selected population as people per cell. Maps optional. Do not round machine-readable metrics to integers. Explicitly state incomplete country coverage and the 2018 source/event dates.

Delivery format: provide the answer object with all fields specified above as final_response on assess_result, alongside the inspected final artifact_refs. This replaces the JSON-code-block formatting requirement above. Blue attaches your explicit selection to the accepted final answer. Finish with a concise ordinary-language answer agreeing with that selected result; do not duplicate the JSON in chat.

Supplied immutable inputs:
[
  {
    "name": "Bangladesh population density, WorldPop 2018",
    "edition": "2018 UN-adjusted 1 km density; exact bytes verified against WorldPop product 45189, DOI WP00675",
    "units": {
      "band1": "people/km\u00b2"
    },
    "collectionId": "blue-generated--[resource id withheld]",
    "itemId": "[resource id withheld]",
    "assetKey": "data"
  },
  {
    "name": "GFD observed flood 4665, 2018-08-02 to 2018-08-10",
    "edition": "Original five-band GFD v1 benchmark snapshot, not a current flood map; benchmark-only use",
    "units": {
      "band1": "binary flooded flag",
      "band2": "days",
      "band3": "observations",
      "band4": "fraction",
      "band5": "binary permanent-water flag"
    },
    "collectionId": "blue-generated--[resource id withheld]",
    "itemId": "[resource id withheld]",
    "assetKey": "data"
  }
]

Outcome & verification

Independent artifact and delivery checks passed.

Duration
22m 46s
Recorded Blue tool calls
63
Total tokens
3,866,493
Model cost
Not recorded
Application revision
d50497ea9084f29c91b05406688f87035df98d8a
Release
terra-geobenchx-v1

Recorded final answer

In the observed part of Bangladesh covered by the supplied GFD event from 2018-08-02 to 2018-08-10, observed flooded cells were less densely populated than observed non-flooded cells: 1,024.77 vs 1,171.64 people/km². This is an observed-footprint result on the frozen 2018 WorldPop Bangladesh grid, not an exhaustive Bangladesh August 2018 total. The published selected-population and classification rasters are ready if you want to inspect them on the map. ### Limitations - The flood event covers only an observed footprint for part of Bangladesh and part of August 2018, so the result is not an exhaustive national monthly total. - Permanent water, cloud gaps, and unobserved cells remain unknown or excluded; they do not prove no flooding. - Observed-footprint only: the supplied GFD event covers part of Bangladesh and part of August 2018, so this is not an exhaustive Bangladesh August 2018 national total. - Unknown or excluded population-grid cells remain NoData; permanent water, cloud gaps, and unobserved areas do not establish non-flooding. - Affected here means people represented by observed flooded population-cell centres on the frozen 2018 population grid, not proven personal impacts. - The supplied flood raster is the benchmark GFD snapshot for 2018-08-02 to 2018-08-10, not a current flood map. - Observed-footprint only: this raster covers the supplied GFD event footprint within the frozen 2018 Bangladesh population grid, not all Bangladesh cells in August 2018. - Unknown or excluded cells remain NoData; permanent water, cloud gaps, and unobserved areas do not establish non-flooding. - Affected here means people represented by observed flooded population-cell centres, not proven personal impacts. - NoData marks unknown or excluded cells, including permanent water, cloud gaps, and unobserved areas; those cells do not establish non-flooding. - The final answer still describes only the supplied Bangladesh population grid, not any wider region. - Unknown cells remain unknown because permanent water, cloud gaps, and unobserved cells do not establish non-flooding. - The density comparison applies only to observed flooded and observed non-flooded cells in the event footprint. - The final machine-readable answer will cite the supplied 2018 population source and the supplied 2018-08-02 to 2018-08-10 event dates.

Independent checks

These checks are separate from the agent's own assessment. A successful job or an assertion of success is not enough to pass.

Expected count
12177
Reported count
12177
Computation verified
Yes
Answer fulfilled
Yes
Full grading and rubric record
{
  "expectedCount": 12177,
  "actualCount": 12177,
  "expectedMetrics": {
    "selected_people": 9671176.237595195,
    "nonflood_people": 23097522.354472633,
    "selected_area_km2": 9437.43836989379,
    "nonflood_area_km2": 19713.91445538982,
    "selected_density": 1024.7670881165218,
    "nonflood_density": 1171.635516971503
  },
  "actualMetrics": {
    "nonflood_people": 23097522.36807418,
    "selected_people": 9671176.246214867,
    "nonflood_density": 1171.6355673299754,
    "selected_density": 1024.7670882428263,
    "nonflood_area_km2": 19713.914473176003,
    "selected_area_km2": 9437.438377141953
  },
  "computationCorrect": true,
  "answerFulfilled": true,
  "adjudication": null,
  "qualification": null,
  "reasons": []
}

Recorded investigation findings

The agent's reported hypotheses and assessments, retained as evidence of its process—not independent proof that the answer is correct. Failed calls retain their requested verdict, not an accepted assessment.

run_trial · completed

Does the full native-grid method correctly classify observed flooded versus observed non-flooded population cells, preserve unknown cells as NoData, and recover the requested totals and areas from complete raster statistics without resampling the population raster?

assess_trial · completed · assessment: sufficient

The private full-area trial preserved the supplied Bangladesh population grid at 559 by 728 cells and aligned the supplied flood bands to that grid with nearest sampling. The final classification raster contained only 0, 1, and NoData, with 37,577 observed cells, 12,177 observed flooded cells, and 369,375 unknown or excluded cells. Producer observations reported zero valid output cells created from missing flood or population inputs. The selected-population raster used people-per-cell units, retained NoData outside observed cells, and complete raster statistics returned flooded people, non-flood people, flooded area, and non-flood area totals needed for the requested comparison.

assess_result · failed · requested assessment: sufficient

The final published outputs confirm an observed-footprint comparison on the unchanged 2018 Bangladesh population grid. Observed flooded cells number 12,177 and unknown or excluded population-grid cells number 369,375. Summed over observed flooded cells, the selected population is 9,671,176.246214867 people across 9,437.438377141953 km2, giving 1,024.7670882428263 people/km2. Summed over observed non-flooded cells, the population is 23,097,522.36807418 people across 19,713.914473176003 km2, giving 1,171.6355673299753 people/km2. The published classification raster is dimensionless 1/0/NoData on the same native grid, and the published selected-population raster is people per cell with zero in observed non-flooded cells and NoData elsewhere.

assess_result · completed · assessment: sufficient

The final published outputs confirm an observed-footprint comparison on the unchanged 2018 Bangladesh population grid. Observed flooded cells number 12,177 and unknown or excluded population-grid cells number 369,375. Summed over observed flooded cells, the selected population is 9,671,176.246214867 people across 9,437.438377141953 km2, giving 1,024.7670882428263 people/km2. Summed over observed non-flooded cells, the population is 23,097,522.36807418 people across 19,713.914473176003 km2, giving 1,171.6355673299754 people/km2. The published classification raster is dimensionless 1/0/NoData on the same native grid, and the published selected-population raster is people per cell with zero in observed non-flooded cells and NoData elsewhere.

assess_result · completed · assessment: sufficient

The published selected-population raster is on the unchanged Bangladesh 2018 population grid and uses people-per-cell units. It is valid only on the 37,577 observed cells, has zero as its minimum value for observed non-flooded cells, and leaves the remaining 369,375 unknown or excluded population-grid cells as NoData.

assess_result · completed · assessment: sufficient

The published classification raster is on the unchanged Bangladesh 2018 population grid and uses dimensionless 1, 0, and NoData values exactly as requested. It contains 37,577 observed cells, of which 12,177 are flooded, and leaves the remaining 369,375 population-grid cells as unknown or excluded NoData.

Recorded workflow

  1. 01

    Population cell area

    Recorded raster-cell-area · succeeded

  2. 02

    Flood classification

    Recorded raster-map-algebra · succeeded

  3. 03

    Classification statistics

    Recorded raster-statistics · succeeded

  4. 04

    Observed flooded population per cell

    Recorded output · succeeded

  5. 05

    Observed flood classification

    Recorded output · succeeded

  6. 06

    Observed flood classification counts

    Recorded output · succeeded

  7. 07

    Observed flooded population total

    Recorded output · succeeded

  8. 08

    Observed non-flood population total

    Recorded output · succeeded

  9. 09

    Observed flooded area total

    Recorded output · succeeded

  10. 10

    Observed non-flood area total

    Recorded output · succeeded

  11. 11

    GFD flood 4665

    Recorded source · succeeded

  12. 12

    Flooded flag on population grid

    Recorded raster-align · succeeded

  13. 13

    Flood band 1

    Recorded raster-extract-band · succeeded

  14. 14

    Clear views on population grid

    Recorded raster-align · succeeded

  15. 15

    Flood band 3

    Recorded raster-extract-band · succeeded

  16. 16

    Permanent water on population grid

    Recorded raster-align · succeeded

  17. 17

    Flood band 5

    Recorded raster-extract-band · succeeded

  18. 18

    Observed non-flood area

    Recorded raster-map-algebra · succeeded

  19. 19

    Observed non-flood area statistics

    Recorded raster-statistics · succeeded

  20. 20

    Observed non-flood population

    Recorded raster-map-algebra · succeeded

  21. 21

    Observed non-flood population statistics

    Recorded raster-statistics · succeeded

  22. 22

    Observed mask

    Recorded raster-map-algebra · succeeded

  23. 23

    Bangladesh population density 2018

    Recorded source · succeeded

  24. 24

    People per cell

    Recorded raster-map-algebra · succeeded

  25. 25

    Observed flooded area

    Recorded raster-map-algebra · succeeded

  26. 26

    Observed flooded area statistics

    Recorded raster-statistics · succeeded

  27. 27

    Selected population

    Recorded raster-map-algebra · succeeded

  28. 28

    Selected population statistics

    Recorded raster-statistics · succeeded

  29. 29

    Population cell area

    Recorded raster-cell-area · succeeded

  30. 30

    Flood classification

    Recorded raster-map-algebra · succeeded

  31. 31

    Classification statistics

    Recorded raster-statistics · succeeded

  32. 32

    GFD flood 4665

    Recorded source · succeeded

  33. 33

    Flooded flag on population grid

    Recorded raster-align · succeeded

  34. 34

    Flood band 1

    Recorded raster-extract-band · succeeded

  35. 35

    Clear views on population grid

    Recorded raster-align · succeeded

  36. 36

    Flood band 3

    Recorded raster-extract-band · succeeded

  37. 37

    Permanent water on population grid

    Recorded raster-align · succeeded

  38. 38

    Flood band 5

    Recorded raster-extract-band · succeeded

  39. 39

    Observed non-flood area

    Recorded raster-map-algebra · succeeded

  40. 40

    Observed non-flood area statistics

    Recorded raster-statistics · succeeded

  41. 41

    Observed non-flood population

    Recorded raster-map-algebra · succeeded

  42. 42

    Observed non-flood population statistics

    Recorded raster-statistics · succeeded

  43. 43

    Observed mask

    Recorded raster-map-algebra · succeeded

  44. 44

    Bangladesh population density 2018

    Recorded source · succeeded

  45. 45

    People per cell

    Recorded raster-map-algebra · succeeded

  46. 46

    Observed flooded area

    Recorded raster-map-algebra · succeeded

  47. 47

    Observed flooded area statistics

    Recorded raster-statistics · succeeded

  48. 48

    Selected population

    Recorded raster-map-algebra · succeeded

  49. 49

    Selected population statistics

    Recorded raster-statistics · succeeded

  50. 50

    Flood classification

    Recorded output · succeeded

  51. 51

    Selected population

    Recorded output · succeeded

  52. 52

    Classification statistics

    Recorded output · succeeded

  53. 53

    Selected population statistics

    Recorded output · succeeded

  54. 54

    Observed non-flood population statistics

    Recorded output · succeeded

  55. 55

    Observed flooded area statistics

    Recorded output · succeeded

  56. 56

    Observed non-flood area statistics

    Recorded output · succeeded

Activity

Recorded actions

Recorded observable actions only, not private reasoning. Raw payloads, geometry, private links and credentials are omitted; full evidence is retained privately. Activity/workflow lists bounded at 500 entries.

  1. Progress update

    I’ll build this from the supplied 2018 population and flood rasters only, test the native-grid method on a small private slice first, then run the full observed-footprint comparison and publish the two required rasters.

  2. get_analysis

    Recorded tool call · completed

  3. Progress update

    I found no prior saved work for this request. Next I’m checking the two supplied rasters’ metadata and exact authorized item selections so I can keep the population grid unchanged and verify the flood footprint really matches the Bangladesh event coverage described.

  4. get_collection

    Recorded tool call · completed

  5. get_collection

    Recorded tool call · completed

  6. get_item

    Recorded tool call · completed

  7. get_item

    Recorded tool call · completed

  8. list_processors

    Recorded tool call · completed

  9. list_processors

    Recorded tool call · completed

  10. list_processors

    Recorded tool call · completed

  11. list_processors

    Recorded tool call · completed

  12. list_processors

    Recorded tool call · completed

  13. list_processors

    Recorded tool call · completed

  14. list_processors

    Recorded tool call · completed

  15. list_processors

    Recorded tool call · completed

  16. describe_processors

    Recorded tool call · completed

  17. describe_processors

    Recorded tool call · completed

  18. describe_processors

    Recorded tool call · completed

  19. describe_processors

    Recorded tool call · completed

  20. Progress update

    I’ve confirmed the supplied rasters and their extents. The flood snapshot is much wider than Bangladesh, so I’m using the Bangladesh population grid as the analysis frame and now checking the exact processor contracts for nearest-grid flood sampling, ellipsoidal cell area, and NoData-safe raster math before I run a private native-grid test.

  21. describe_processors

    Recorded tool call · completed

  22. describe_processors

    Recorded tool call · completed

  23. get_tool_help

    Recorded tool call · completed

  24. describe_processors

    Recorded tool call · completed

  25. get_tool_help

    Recorded tool call · completed

  26. search_knowledge

    Recorded tool call · completed

  27. inspect_artifact

    Recorded tool call · failed

  28. inspect_artifact

    Recorded tool call · failed

  29. inspect_artifact

    Recorded tool call · failed

  30. inspect_artifact

    Recorded tool call · failed

  31. update_analysis_brief

    Recorded tool call · completed

  32. get_tool_help

    Recorded tool call · completed

  33. search_knowledge

    Recorded tool call · completed

  34. search_knowledge

    Recorded tool call · completed

  35. Progress update

    I’ve got a workable method: extract flood bands 1, 3, and 5, align them to the unchanged population grid with nearest sampling, compute ellipsoidal cell area from the population grid, convert density to people per cell, then build the required classification and selected-population rasters plus full-grid statistics. I’m running that privately now to confirm the NoData rules and counts before I save the production workflow.

  36. run_trial

    Recorded tool call · completed

  37. Progress update

    The private full-grid test finished successfully. I’m checking the saved trial report and then I’ll turn that tested method into the production workflow so the two required rasters and metrics can be published from the same native-grid logic.

  38. get_trial_report

    Recorded tool call · completed

  39. Progress update

    The test answered the main uncertainty: the method kept the original Bangladesh grid, left unknown cells as NoData, and produced consistent flooded and non-flooded totals from the same observed cells. I’m recording that result and saving the production workflow from this tested full-area computation.

  40. assess_trial

    Recorded tool call · completed

  41. update_analysis_brief

    Recorded tool call · completed

  42. get_tool_help

    Recorded tool call · completed

  43. get_tool_help

    Recorded tool call · completed

  44. get_tool_help

    Recorded tool call · completed

  45. get_tool_help

    Recorded tool call · completed

  46. get_tool_help

    Recorded tool call · completed

  47. get_tool_help

    Recorded tool call · completed

  48. Progress update

    I have the tested full-area method and the core numbers from the private run. Next I’m saving that exact computation as a publishable workflow with the two native-grid rasters plus the supporting summary tables that back the final density comparison.

  49. propose_workflow

    Recorded tool call · completed

  50. Progress update

    The publishable workflow is saved and ready. It reuses the same tested full-area computation, with only runtime grid checks left for execution, so I’m starting that run now and will inspect the final artifact IDs and summary tables before I record the answer object.

  51. execute_workflow

    Recorded tool call · completed

  52. Progress update

    The production run has completed, so I’m inspecting the exact published outputs now. I’ll verify the two rasters and the five summary tables, then record the final answer object with their selected artifact identities and the observed-footprint metrics.

  53. inspect_workflow_results

    Recorded tool call · completed

  54. Progress update

    The run is done. I’m pulling the final deliverable receipts directly so I can verify the published raster identities and the one-row summary tables before I record the selected result.

  55. inspect_workflow_results

    Recorded tool call · completed

  56. Progress update

    I’ve got the final artifact identities. Now I’m reading the two published rasters and the five one-row summary tables directly so the recorded answer uses the actual final outputs, not just the earlier trial numbers.

  57. inspect_artifact

    Recorded tool call · completed

  58. inspect_artifact

    Recorded tool call · completed

  59. inspect_artifact

    Recorded tool call · completed

  60. inspect_artifact

    Recorded tool call · completed

  61. inspect_artifact

    Recorded tool call · completed

  62. inspect_artifact

    Recorded tool call · completed

  63. inspect_artifact

    Recorded tool call · completed

  64. Progress update

    I already have the final published artifact IDs. I’m just completing the bounded inspections now so the recorded answer cites the exact final rasters and tables from this run.

  65. inspect_artifact

    Recorded tool call · completed

  66. inspect_artifact

    Recorded tool call · completed

  67. inspect_artifact

    Recorded tool call · completed

  68. inspect_artifact

    Recorded tool call · completed

  69. inspect_artifact

    Recorded tool call · completed

  70. inspect_artifact

    Recorded tool call · completed

  71. inspect_artifact

    Recorded tool call · completed

  72. assess_result

    Recorded tool call · failed

  73. Progress update

    I hit a formatting check on the final assessment, not a data problem. I’m resubmitting it with the exact acceptance-condition wording from the saved result so Blue can attach the selected answer object to the verified outputs.

  74. assess_result

    Recorded tool call · completed

  75. Progress update

    I’ve already inspected the two final rasters, so I’m just recording their own result checks now. That closes the remaining verification items Blue flagged for the published map outputs.

  76. assess_result

    Recorded tool call · completed

  77. assess_result

    Recorded tool call · completed

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