{
  "title": "Course mapping output field definitions",
  "steward": "Tyler Hinkle, jth4qt@virginia.edu",
  "crs": "EPSG:4326, longitude then latitude for exported GeoJSON",
  "extent": "The student-selected visible study area or supplied file extent. Course focus: Southwest Virginia.",
  "lineage": "FEMA / ORNL USA Structures for queried building footprints; US Census TIGERweb Transportation for street lines; student-supplied files and drawn observations for additional evidence.",
  "use_constraints": "Planning and instruction. Not survey-grade, legal parcel boundaries, or engineering design. Online reference overlays are not a substitute for agency review. Preserve source vintage and missing-data descriptions.",
  "fields": {
    "parcel": {"alias":"Practice parcel label","description":"A fictional row label in the worked example; not an actual parcel ID."},
    "assessed_value": {"alias":"Practice assessed value","description":"Fictional dollar value used to demonstrate the calculation. Null means unavailable."},
    "acres": {"alias":"Practice parcel area","description":"Fictional acreage used to demonstrate validation. Zero is deliberately invalid for division."},
    "exempt": {"alias":"Practice exemption label","description":"Fictional yes/no flag used to demonstrate explicit exemption handling."},
    "use": {"alias":"Practice land-use category","description":"Fictional category for comparing like uses."},
    "source": {"alias":"Source statement","description":"Provenance or explicit fictional-example label."},
    "lng": {"alias":"Longitude","description":"East-west coordinate in WGS 84 decimal degrees."},
    "lat": {"alias":"Latitude","description":"North-south coordinate in WGS 84 decimal degrees."},
    "OBJECTID": {"alias":"Source object ID","description":"Identifier assigned by the source service; not a parcel identifier."},
    "road_class": {"alias":"Road class","description":"Primary, secondary, or local source road layer."},
    "name": {"alias":"Road name","description":"Road label supplied by the source, blank when unavailable."},
    "label": {"alias":"Student annotation","description":"Student-entered description of a mapped observation, line, or area."},
    "slope_pct": {"alias":"Slope, percent","description":"Rise divided by horizontal run, multiplied by 100. Values from a degrees field are converted with tan(degrees) times 100. Missing values stay unclassified."},
    "_course_value": {"alias":"Assessed value","description":"Numeric value copied from the student-selected assessment field. It is not tax revenue."},
    "_course_acres": {"alias":"Parcel area, acres","description":"Positive parcel acreage from the student-selected area field."},
    "_course_vpa": {"alias":"Assessed value per acre","description":"Assessed value divided by positive parcel acreage. Rendering height is a proportional symbol, not building height."},
    "_course_exempt": {"alias":"Public or exempt flag","description":"True or false only when the source flag is recognized; null when unknown. Unknown does not mean taxable."}
  }
}