> ## Documentation Index
> Fetch the complete documentation index at: https://docs.worlds.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Type I: Track in Zone

> Check if a track's interaction with configured zones meets threshold conditions

Type I checks evaluate whether a track is present in specific zones and whether its zone interaction metrics (intersection, dwell time, velocity) meet configured thresholds.

## When to use

Use Type I for any use case where the core question is "is this object in this zone doing this thing?":

* **Obstruction / loitering** — dwell time above threshold, velocity below threshold
* **Zone intrusion** — any presence in a restricted zone with minimum intersection
* **Congestion** — multiple tracks in a zone exceeding thresholds
* **Speeding** — velocity above threshold in a zone
* **Stopped vehicle** — velocity below threshold for extended dwell time

## How it works

1. The node reads the track's zone data (active zones for live data, historical zones for expired tracks)
2. For each zone that has a threshold configuration, it evaluates **all enabled thresholds**
3. A zone passes if **all** enabled thresholds pass (AND logic within a zone)
4. The overall check passes if **at least one** zone passes (OR logic across zones)

## Configuration

### Site

Select the Worlds site. This loads the available zones for threshold configuration.

### Threshold groups

Threshold groups define which zones to check and what thresholds to apply. Each group contains:

| Parameter        | Description                                                            |
| ---------------- | ---------------------------------------------------------------------- |
| **Zone IDs**     | Which zones this group applies to                                      |
| **Intersection** | Minimum overlap between the object's bounding box and the zone polygon |
| **Dwell Time**   | How long the object has been in the zone                               |
| **Velocity**     | How fast the object is moving within the zone                          |

Each threshold has:

* **Enable toggle** — only enabled thresholds are evaluated
* **Operator** — `>=`, `>`, `<=`, `<`, `==`
* **Value** — the threshold value

**Threshold units:**

| Threshold    | Unit        | Description                                     |
| ------------ | ----------- | ----------------------------------------------- |
| Intersection | % (0–100)   | Percentage of bounding box overlapping the zone |
| Dwell Time   | seconds     | Time spent in the zone                          |
| Velocity     | px/s or m/s | Speed within the zone (pixel or geo-referenced) |

<Tip>
  You can create multiple threshold groups to apply different thresholds to different zones. A zone can only belong to one group.
</Tip>

### Advanced settings

| Parameter        | Default | Description                                                            |
| ---------------- | ------- | ---------------------------------------------------------------------- |
| **Check Target** | Auto    | `auto` detects from trigger mode. Override with `active` or `history`. |
| **Debug Mode**   | false   | Enable verbose logging                                                 |

## Output

```json theme={null}
{
  "track_state": { ... },
  "checks": {
    "type1": {
      "passed": true,
      "check_target": "active",
      "check_target_source": "auto",
      "matching_zones": ["79"],
      "matching_zone_count": 1,
      "zone_details": {
        "79": {
          "zone_id": "79",
          "zone_name": "op120-zone",
          "source": "active",
          "passed": true,
          "thresholds": {
            "intersection": {
              "enabled": true,
              "operator": ">=",
              "threshold": 10,
              "actual": 59.25,
              "passed": true,
              "unit": "%"
            },
            "dwellTime": {
              "enabled": true,
              "operator": ">=",
              "threshold": 300,
              "actual": 360,
              "passed": true,
              "unit": "seconds"
            },
            "velocity": {
              "enabled": true,
              "operator": "<",
              "threshold": 5,
              "actual": 1.2,
              "passed": true,
              "unit": "px/s"
            }
          }
        }
      },
      "zones_checked": ["79"],
      "zones_not_configured": ["42"],
      "zones_not_found": []
    }
  }
}
```

### Key output fields

| Field                  | Description                                                                                     |
| ---------------------- | ----------------------------------------------------------------------------------------------- |
| `passed`               | Whether any zone met all thresholds                                                             |
| `matching_zones`       | Zone IDs that passed                                                                            |
| `zone_details`         | Per-zone breakdown showing each threshold's actual vs. configured value                         |
| `zones_checked`        | Zones that were evaluated (had threshold config and were present in input)                      |
| `zones_not_configured` | Zones the track was in but had no threshold config                                              |
| `reason`               | If failed: `no_zones_configured`, `no_zones_data_in_input`, `no_zones_met_all_thresholds`, etc. |

## Business use case examples

<Accordion title="Obstruction detection — dwell + intersection + velocity">
  Detect vehicles (forklifts, tuggers, AMRs) blocking factory aisles. A vehicle is considered an obstruction when it has been in an aisle zone for an extended period with low velocity.

  | Threshold        | Operator | Value          | Purpose                                               |
  | ---------------- | -------- | -------------- | ----------------------------------------------------- |
  | **Intersection** | `>=`     | `10%`          | Vehicle bounding box must overlap the zone            |
  | **Dwell Time**   | `>=`     | `300s` (5 min) | Vehicle must have been stopped for at least 5 minutes |
  | **Velocity**     | `<`      | `5 px/s`       | Vehicle must be stationary or near-stationary         |

  **Mode:** Batch — only need the track summary after the vehicle leaves.

  All three thresholds are enabled, so a zone only passes if all three conditions are met simultaneously. Different aisle zones can share a single threshold group if they have the same criteria, or use separate groups for zones with different dwell time requirements (e.g., loading docks allow longer stops).

  See the [Obstruction Workflow](/guides/batch-track-state) guide for the full end-to-end walkthrough.
</Accordion>

<Accordion title="Failure to stop — velocity only, multiple threshold groups">
  Detect vehicles that fail to come to a complete stop at designated stop sign zones. This is a **compliance monitoring** pattern — every vehicle passing through creates an event, either compliant or non-compliant.

  | Threshold    | Operator | Value                  | Purpose                                                                   |
  | ------------ | -------- | ---------------------- | ------------------------------------------------------------------------- |
  | **Velocity** | `<=`     | `25–120 px/s` (varies) | Vehicle's average velocity must be at or below the zone's speed threshold |

  **Mode:** Batch — only need the track summary after the vehicle passes through.

  The key detail: **10 separate threshold groups** with different velocity values. Zones near intersections have lower thresholds (stricter stops), while zones in high-traffic corridors have higher thresholds. Each stop zone is assigned to exactly one group.

  A code node downstream preserves the original pass/fail result as `threshold_passed`, then overrides `type1.passed = true` so that **both** compliant and non-compliant tracks flow through to event creation. The event subtype is set dynamically based on the saved result.
</Accordion>

<Accordion title="PPE zone pre-filter — intersection only">
  As a pre-filter in the PPE compliance workflow, Type I determines whether a person is in a designated PPE zone before evaluating whether they're wearing PPE (via a Type III check).

  | Threshold        | Operator | Value | Purpose                               |
  | ---------------- | -------- | ----- | ------------------------------------- |
  | **Intersection** | `>=`     | `10%` | Person must be in a PPE-required zone |

  **Mode:** Batch — using person and PPE tags together so interactions are calculated.

  Only intersection is enabled — no dwell time or velocity requirements. The check simply answers "is this person in a zone that requires PPE?" Tracks that fail are dropped via an early-exit Switch node before running the more expensive Type III interaction check.

  This demonstrates how Type I can be used as a **lightweight filter** in a multi-check composition (Type I → Type III → VLM fallback).
</Accordion>

<Accordion title="Adapting thresholds for other use cases">
  Type I is the most flexible check node — different threshold combinations serve very different use cases:

  | Use Case               | Intersection | Dwell Time | Velocity     |
  | ---------------------- | ------------ | ---------- | ------------ |
  | Aisle obstruction      | `>= 10%`     | `>= 300s`  | `< 5 px/s`   |
  | Loading dock overstay  | `>= 20%`     | `>= 1800s` | `< 2 px/s`   |
  | No-park zone violation | `>= 10%`     | `>= 60s`   | `< 3 px/s`   |
  | Zone intrusion         | `>= 5%`      | —          | —            |
  | Speeding in zone       | `>= 10%`     | —          | `> 200 px/s` |
  | Stop compliance        | —            | —          | `<= 50 px/s` |

  The key principle: enable only the thresholds you need for your specific use case. Fewer enabled thresholds means a broader match.
</Accordion>

## Active vs. historical zones

| Check Target | Source          | When                                              |
| ------------ | --------------- | ------------------------------------------------- |
| **Active**   | `zones.active`  | Streaming/live — zones the track is currently in  |
| **History**  | `zones.history` | Batch/expired — zones the track was previously in |

For historical zones, the node uses **"any entry passes" logic** — if a track visited the same zone multiple times, only one entry needs to pass all thresholds.

## Credentials

Requires **GraphQL Subscription API** credentials (for loading site/zone options).