# Tree Canopy Observations — Category Frequencies + Two-Measure Correlation

> Tree Canopy Observations — Category Frequencies + Two-Measure Correlation is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-24).

Computes category frequencies and Pearson/Spearman correlation between canopy_m2 and plot_m2 fields across up to 200 supplied tree canopy observation rows.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-ib26-weather-17-108?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tree-canopy-observations-category-frequencies-two-measure-correlation-19732e2e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iGI4TC7qCWkFTuJ0r4DIP

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability tree-canopy-observations-category-frequencies-two-measure-correlation-19732e2e -d '<json body>'
```

Example prompt: I have up to 200 tree canopy observation records with station_group, date, canopy_m2, and plot_m2 fields — can you run category frequency counts on the station groups and also compute the correlation between canopy_m2 and plot_m2?

## When to prefer this

Choose this endpoint when you have up to 200 pre-collected tree canopy observation records and need both a categorical breakdown of station groups and a correlation between two numeric measures (canopy_m2 and plot_m2) in a single low-cost call. Prefer it over general statistics APIs when your data specifically involves canopy and plot area measurements and you want two bundled analytical outputs for $0.01 USDC. Not suitable for live sensor data lookup, predictions, or datasets exceeding 200 rows.

## Known failure modes

- Fewer than 1 row supplied — request rejected
- More than 200 rows supplied — exceeds maximum limit
- Missing required fields (row_id, station_group, date, canopy_m2, plot_m2) — validation error
- Dates not matching YYYY-MM-DD pattern — schema validation failure
- All canopy_m2 or plot_m2 values null — correlation cannot be computed
- Payment not provided or incorrect amount — x402 payment required error

## How this service works

Tree canopy observations — Category frequencies + Two-measure correlation: Category frequencies + Two-measure correlation for supplied tree canopy observations records (canopy_m2, plot_m2). Up to 200 rows; 2 independent reports using shared local analytical engines. No live lookup, prediction, professional assessment or external action. 0.01 USDC includes 2 supplied-data reports for up to 200 rows.

## Output

Returns two analytical reports sharing the same input rows: (1) a frequency table showing how many records fall into each station_group category, and (2) a two-measure correlation result quantifying the statistical relationship between canopy_m2 and plot_m2 values across the supplied rows.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "rows": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "row_id",
     "station_group",
     "date",
     "canopy_m2",
     "plot_m2"
    ],
    "properties": {
     "date": {
      "type": "string",
      "default": "",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
      "maxLength": 10
     },
     "row_id": {
      "type": "string",
      "default": "",
      "maxLength": 80,
      "minLength": 1
     },
     "plot_m2": {
      "type": [
       "number",
       "null"
      ],
      "maximum": 1000000000000,
      "minimum": -1000000000000
     },
     "canopy_m2": {
      "type": [
       "number",
       "null"
      ],
      "maximum": 1000000000000,
      "minimum": -1000000000000
     },
     "station_group": {
      "type": "string",
      "default": "",
      "maxLength": 80
     }
    },
    "additionalProperties": false
   },
   "default": [
    {
     "date": "2026-10-01",
     "row_id": "row-1",
     "plot_m2": 1,
     "canopy_m2": 10,
     "station_group": "group-a"
    },
    {
     "date": "2026-10-02",
     "row_id": "row-2",
     "plot_m2": 2,
     "canopy_m2": 20,
     "station_group": "group-b"
    },
    {
     "date": "2026-10-03",
     "row_id": "row-3",
     "plot_m2": 3,
     "canopy_m2": 15,
     "station_group": "group-a"
    },
    {
     "date": "2026-10-04",
     "row_id": "row-4",
     "plot_m2": 4,
     "canopy_m2": 30,
     "station_group": "group-b"
    }
   ],
   "maxItems": 200,
   "minItems": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tree-canopy-observations-category-frequencies-two-measure-correlation-19732e2e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)