Add validate_geojson_tool for offline GeoJSON validation

[mattpodwysocki]

Summary

Adds a comprehensive offline GeoJSON validation tool that checks GeoJSON objects for correctness without requiring API access.

Features

• ✅ Validates all GeoJSON types:

  • Feature, FeatureCollection
  • Point, MultiPoint
  • LineString, MultiLineString
  • Polygon, MultiPolygon
  • GeometryCollection

• ✅ Comprehensive validation checks:

  • GeoJSON type validity
  • Required properties (type, coordinates, geometry, features)
  • Coordinate array structure
  • Position validity (lon/lat ranges)
  • Polygon ring closure
  • Minimum position requirements

• ✅ Structured validation results:

  • valid boolean flag
  • errors array (critical issues)
  • warnings array (non-critical issues)
  • info array (informational messages)
  • statistics object (type, feature count, geometry types, bbox)

• ✅ Developer-friendly:

  • Detailed error messages with JSON paths
  • Actionable suggestions for fixing issues
  • Accepts both JSON strings and objects as input

Implementation Details

• Architecture: Extends BaseTool (offline, no HttpRequest dependency)
• Testing: 28 comprehensive test cases covering:
  • Valid GeoJSON of all types
  • Invalid structure detection
  • Coordinate validation
  • Error handling
  • Statistics calculation
• Documentation: Added to README with examples and usage patterns

Test Results

All 398 tests pass ✅

Example Usage

{
  "geojson": {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [102.0, 0.5]
    },
    "properties": {
      "name": "Test Point"
    }
  }
}

Returns:

{
  "valid": true,
  "errors": [],
  "warnings": [],
  "info": [],
  "statistics": {
    "type": "Feature",
    "featureCount": 1,
    "geometryTypes": ["Point"],
    "bbox": [102.0, 0.5, 102.0, 0.5]
  }
}

Related

Part of a series of offline validation tools being added to the server. This is the second tool after validate_style_tool (#49).

Test Plan

Test 1: Valid Point Feature ✅

Can you validate this GeoJSON?

  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [-122.4194, 37.7749]
    },
    "properties": {
      "name": "San Francisco"
    }
  }

Expected: Valid, returns statistics (1 feature, Point geometry, bbox)

Test 2: Valid Polygon ✅

Validate this polygon:

  {
    "type": "Polygon",
    "coordinates": [
      [
        [-122.4, 37.8],
        [-122.4, 37.7],
        [-122.3, 37.7],
        [-122.3, 37.8],
        [-122.4, 37.8]
      ]
    ]
  }

Expected: Valid, polygon ring is properly closed (first and last coordinates match)

Test 3: Invalid Coordinates (Out of Range) ❌

Check if this GeoJSON is valid:

  {
    "type": "Point",
    "coordinates": [200.0, 100.0]
  }

Expected:

• Invalid
• Error: Longitude out of range (200.0 should be -180 to 180)
• Error: Latitude out of range (100.0 should be -90 to 90)

Test 4: Unclosed Polygon ❌

Is this polygon valid?

  {
    "type": "Polygon",
    "coordinates": [
      [
        [0, 0],
        [10, 0],
        [10, 10],
        [0, 10]
      ]
    ]
  }

Expected:

• Invalid
• Error: Polygon ring not closed (first and last coordinates must match)
• Suggestion: Add closing coordinate [0, 0]

Test 5: Valid FeatureCollection ✅

Validate this collection:

  {
    "type": "FeatureCollection",
    "features": [
      {
        "type": "Feature",
        "geometry": {
          "type": "Point",
          "coordinates": [-73.9857, 40.7484]
        },
        "properties": {"name": "NYC"}
      },
      {
        "type": "Feature",
        "geometry": {
          "type": "Point",
          "coordinates": [-118.2437, 34.0522]
        },
        "properties": {"name": "LA"}
      }
    ]
  }

Expected:

• Valid
• Statistics: 2 features, all Point geometries
• Bounding box covering both NYC and LA

Test 6: Wrong Coordinate Order (Common Mistake) ⚠️

Check this point:

  {
    "type": "Point",
    "coordinates": [37.7749, -122.4194]
  }

Expected:

• Technically valid (coordinates are within range)
• But this is lat,lon order (incorrect) instead of lon,lat
• The tool validates ranges but can't detect coordinate order issues
• Good test to see if Claude mentions this common mistake