Geo Analytics

Scenario: CityDrive records precise GPS positioning and distance-to-signal for every flagged frame. This geospatial data originates from the dash-cam's GPS module and is precisely aligned with the timestamps of video keyframes. Ops teams can answer "where did this happen?" purely in SQL.

frame_geo_points and signal_contact_points share the same video_id/frame_id keys as the rest of the guide, so you can move from SQL metrics to maps without copying data.

1. Create Location Tables

If you followed the JSON guide, these tables already exist. The snippet below shows their structure plus a few Shenzhen samples.

CREATE OR REPLACE TABLE frame_geo_points (
    video_id   STRING,
    frame_id   STRING,
    position_wgs84 GEOMETRY,
    solution_grade INT,
    source_system STRING,
    created_at TIMESTAMP
);

INSERT INTO frame_geo_points VALUES
  ('VID-20250101-001','FRAME-0101',TO_GEOMETRY('SRID=4326;POINT(114.0579123456789 22.543123456789)'),104,'fusion_gnss','2025-01-01 08:15:21'),
  ('VID-20250101-001','FRAME-0102',TO_GEOMETRY('SRID=4326;POINT(114.0610987654321 22.546098765432)'),104,'fusion_gnss','2025-01-01 08:33:54'),
  ('VID-20250101-002','FRAME-0201',TO_GEOMETRY('SRID=4326;POINT(114.104012345678 22.559456789012)'),104,'fusion_gnss','2025-01-01 11:12:02'),
  ('VID-20250102-001','FRAME-0301',TO_GEOMETRY('SRID=4326;POINT(114.082265432109 22.53687654321)'),104,'fusion_gnss','2025-01-02 09:44:18'),
  ('VID-20250103-001','FRAME-0401',TO_GEOMETRY('SRID=4326;POINT(114.119501234567 22.544365432101)'),104,'fusion_gnss','2025-01-03 21:18:07');

CREATE OR REPLACE TABLE signal_contact_points (
    node_id     STRING,
    signal_position GEOMETRY,
    video_id    STRING,
    frame_id    STRING,
    frame_position GEOMETRY,
    distance_m  DOUBLE,
    created_at  TIMESTAMP
);

INSERT INTO signal_contact_points VALUES
  ('SIG-0001', TO_GEOMETRY('SRID=4326;POINT(114.058500123456 22.543800654321)'), 'VID-20250101-001', 'FRAME-0101', TO_GEOMETRY('SRID=4326;POINT(114.0579123456789 22.543123456789)'), 0.012345, '2025-01-01 08:15:30'),
  ('SIG-0002', TO_GEOMETRY('SRID=4326;POINT(114.118900987654 22.544800123456)'), 'VID-20250103-001', 'FRAME-0401', TO_GEOMETRY('SRID=4326;POINT(114.119501234567 22.544365432101)'), 0.008765, '2025-01-03 21:18:20');

-- Frames and JSON tables these queries join against (same rows as SQL & Search guides).
CREATE OR REPLACE TABLE frame_events (
    frame_id     STRING,
    video_id     STRING,
    frame_index  INT,
    collected_at TIMESTAMP,
    event_tag    STRING,
    risk_score   DOUBLE,
    speed_kmh    DOUBLE
);

INSERT INTO frame_events VALUES
  ('FRAME-0101', 'VID-20250101-001', 125, '2025-01-01 08:15:21', 'hard_brake',      0.81, 32.4),
  ('FRAME-0102', 'VID-20250101-001', 416, '2025-01-01 08:33:54', 'pedestrian',      0.67, 24.8),
  ('FRAME-0201', 'VID-20250101-002', 298, '2025-01-01 11:12:02', 'lane_merge',      0.74, 48.1),
  ('FRAME-0301', 'VID-20250102-001', 188, '2025-01-02 09:44:18', 'hard_brake',      0.59, 52.6),
  ('FRAME-0401', 'VID-20250103-001', 522, '2025-01-03 21:18:07', 'night_lowlight',  0.63, 38.9),
  ('FRAME-0501', 'VID-MISSING-001', 10, '2025-01-04 10:00:00', 'sensor_fault',     0.25, 15.0);

CREATE OR REPLACE TABLE frame_metadata_catalog (
    doc_id      STRING,
    meta_json   VARIANT,
    captured_at TIMESTAMP,
    INVERTED INDEX idx_meta_json (meta_json)
);

INSERT INTO frame_metadata_catalog VALUES
  ('FRAME-0101', PARSE_JSON('{"scene":{"weather_code":"rain","lighting":"day"},"camera":{"sensor_view":"roof"},"vehicle":{"speed_kmh":32.4},"detections":{"objects":[{"type":"vehicle","confidence":0.88},{"type":"brake_light","confidence":0.64}]},"media_meta":{"tagging":{"labels":["hard_brake","rain","downtown_loop"]}}}'), '2025-01-01 08:15:21'),
  ('FRAME-0102', PARSE_JSON('{"scene":{"weather_code":"rain","lighting":"day"},"camera":{"sensor_view":"roof"},"vehicle":{"speed_kmh":24.8},"detections":{"objects":[{"type":"pedestrian","confidence":0.92},{"type":"bike","confidence":0.35}]},"media_meta":{"tagging":{"labels":["pedestrian","swerve","crosswalk"]}}}'), '2025-01-01 08:33:54'),
  ('FRAME-0201', PARSE_JSON('{"scene":{"weather_code":"overcast","lighting":"day"},"camera":{"sensor_view":"front"},"vehicle":{"speed_kmh":48.1},"detections":{"objects":[{"type":"lane_merge","confidence":0.74},{"type":"vehicle","confidence":0.41}]},"media_meta":{"tagging":{"labels":["lane_merge","urban"]}}}'), '2025-01-01 11:12:02'),
  ('FRAME-0301', PARSE_JSON('{"scene":{"weather_code":"clear","lighting":"day"},"camera":{"sensor_view":"front"},"vehicle":{"speed_kmh":52.6},"detections":{"objects":[{"type":"vehicle","confidence":0.82},{"type":"hard_brake","confidence":0.59}]},"media_meta":{"tagging":{"labels":["hard_brake","highway"]}}}'), '2025-01-02 09:44:18'),
  ('FRAME-0401', PARSE_JSON('{"scene":{"weather_code":"lightfog","lighting":"night"},"camera":{"sensor_view":"rear"},"vehicle":{"speed_kmh":38.9},"detections":{"objects":[{"type":"traffic_light","confidence":0.78},{"type":"vehicle","confidence":0.36}]},"media_meta":{"tagging":{"labels":["night_lowlight","traffic_light"]}}}'), '2025-01-03 21:18:07');

Docs: Geospatial types.

---

2. Spatial Filters

Measure how far each frame was from a key downtown coordinate or check whether it falls inside a polygon. Convert to SRID 3857 when you need meter-level distances.

SELECT l.frame_id,
       l.video_id,
       f.event_tag,
       ST_DISTANCE(
         ST_TRANSFORM(l.position_wgs84, 3857),
         ST_TRANSFORM(TO_GEOMETRY('SRID=4326;POINT(114.0600 22.5450)'), 3857)
       ) AS meters_from_hq
FROM frame_geo_points AS l
JOIN frame_events AS f USING (frame_id)
WHERE ST_DISTANCE(
        ST_TRANSFORM(l.position_wgs84, 3857),
        ST_TRANSFORM(TO_GEOMETRY('SRID=4326;POINT(114.0600 22.5450)'), 3857)
      ) <= 400
ORDER BY meters_from_hq;

Sample output:

frame_id  | video_id         | event_tag  | meters_from_hq
FRAME-0102| VID-20250101-001 | pedestrian | 180.277138577
FRAME-0101| VID-20250101-001 | hard_brake | 324.291965923

Tip: add ST_ASTEXT(l.geom) while debugging or switch to HAVERSINE for great-circle math.

WITH school_zone AS (
    SELECT TO_GEOMETRY('SRID=4326;POLYGON((
        114.0505 22.5500,
        114.0630 22.5500,
        114.0630 22.5420,
        114.0505 22.5420,
        114.0505 22.5500
    ))') AS poly
)
SELECT l.frame_id,
       l.video_id,
       f.event_tag
FROM frame_geo_points AS l
JOIN frame_events AS f USING (frame_id)
CROSS JOIN school_zone
WHERE ST_CONTAINS(poly, l.position_wgs84);

Sample output:

frame_id  | video_id         | event_tag
FRAME-0101| VID-20250101-001 | hard_brake
FRAME-0102| VID-20250101-001 | pedestrian

---

3. Hex Aggregations

Aggregate risky frames into hexagonal buckets for dashboards.

SELECT GEO_TO_H3(ST_X(position_wgs84), ST_Y(position_wgs84), 8) AS h3_cell,
       COUNT(*) AS frame_count,
       AVG(f.risk_score) AS avg_risk
FROM frame_geo_points AS l
JOIN frame_events AS f USING (frame_id)
GROUP BY h3_cell
ORDER BY avg_risk DESC;

Sample output:

h3_cell         | frame_count | avg_risk
613635011200942079| 1          | 0.81
613635011532292095| 1          | 0.74
613635011238690815| 1          | 0.67
613635015391051775| 1          | 0.63
613635011309993983| 1          | 0.59

Docs: H3 functions.

---

4. Traffic Context

Join signal_contact_points and frame_geo_points to validate stored metrics, or blend spatial predicates with JSON search.

SELECT t.node_id,
       t.video_id,
       t.frame_id,
       ST_DISTANCE(t.signal_position, t.frame_position) AS recomputed_distance,
       t.distance_m AS stored_distance,
       l.source_system
FROM signal_contact_points AS t
JOIN frame_geo_points AS l USING (frame_id)
WHERE t.distance_m < 0.03  -- roughly < 30 meters depending on SRID
ORDER BY t.distance_m;

Sample output:

node_id | video_id         | frame_id  | recomputed_distance | stored_distance | source_system
SIG-0002| VID-20250103-001 | FRAME-0401| 0.000741116         | 0.008765        | fusion_gnss
SIG-0001| VID-20250101-001 | FRAME-0101| 0.000896705         | 0.012345        | fusion_gnss

WITH near_junction AS (
    SELECT frame_id
    FROM frame_geo_points
    WHERE ST_DISTANCE(
            ST_TRANSFORM(position_wgs84, 3857),
            ST_TRANSFORM(TO_GEOMETRY('SRID=4326;POINT(114.0830 22.5370)'), 3857)
          ) <= 200
)
SELECT f.frame_id,
       f.event_tag,
       meta.meta_json['media_meta']['tagging']['labels'] AS labels
FROM near_junction nj
JOIN frame_events AS f USING (frame_id)
JOIN frame_metadata_catalog AS meta
  ON meta.doc_id = nj.frame_id
WHERE QUERY('meta_json.media_meta.tagging.labels:hard_brake');

Sample output:

frame_id  | event_tag   | labels
FRAME-0301| hard_brake  | ["hard_brake","highway"]

This pattern lets you filter by geography first, then apply JSON search to the surviving frames.

---

5. Publish a Heatmap View

Expose the geo heatmap to BI or GIS tools without re-running heavy SQL.

CREATE OR REPLACE VIEW v_citydrive_geo_heatmap AS
SELECT GEO_TO_H3(ST_X(position_wgs84), ST_Y(position_wgs84), 7) AS h3_cell,
       COUNT(*)                              AS frames,
       AVG(f.risk_score)                     AS avg_risk
FROM frame_geo_points AS l
JOIN frame_events AS f USING (frame_id)
GROUP BY h3_cell;

Sample output:

h3_cell         | frames | avg_risk
609131411584057343| 1    | 0.81
609131411919601663| 1    | 0.74
609131411617611775| 1    | 0.67
609131415778361343| 1    | 0.63
609131411684720639| 1    | 0.59

Databend now serves vector, text, and spatial queries off the exact same video_id, so investigation teams never have to reconcile separate pipelines.