The Neighbourly Bathymetry API returns lake depth contour lines for Ontario as GeoJSON LineStrings. Each line carries its depth in metres, how and when it was surveyed and how accurately it was placed. Filter to a single depth or a range for any map viewport.
Bathymetry is the measurement of water depth. A lake's bathymetry is usually published as contour lines that join points of equal depth. This API serves those lines for Ontario lakes as GeoJSON. Depth is stored as a negative number of metres below the surface (−4 is 4 m deep), with the survey method, survey date, creation method and positional accuracy of each line.
Ask for one contour with depth=-4, or a band with min_depth and max_depth, for example to shade the shallows from 0 to −3 m.
Query by viewport and draw the lines straight onto a web map. Up to 5,000 lines per request, so a whole bay can come back in one call.
Each line records how it was surveyed (for example GPS or transect), when, how it was digitized and its stated accuracy. Older hand-digitized surveys are clearly marked.
These are the fields the API returns for this layer. Field names match the JSON response exactly.
| Field | Type | Description |
|---|---|---|
| id | integer | Stable Neighbourly line ID |
| depth | float | Contour depth in metres, negative below surface |
| survey_method | string | e.g. GPS, Transect |
| survey_date | datetime | Date of the field survey |
| creation_methodology | string | e.g. Hand Digitized |
| location_accuracy | string | e.g. Within 5 metres |
| lake_boundary_id | integer | Linked lake, where matched |
| ogf_id | integer | Source feature ID (Ontario GeoHub) |
| geom | GeoJSON | LineString geometry |
All requests go to https://api.neighbourly.io and send your key in the Api-Key header. A viewport is a JSON bounding box, {"southWestLat":…,"southWestLon":…,"northEastLat":…,"northEastLon":…}, URL-encoded.
Live response, trimmed. This is the deepest contour in Lake Rosseau, matched by location. Not every line is linked to a lake ID yet, so query by viewport for complete coverage.
{
"id": 105924,
"ogf_id": 320377480,
"depth": -89,
"survey_method": "GPS",
"survey_date": "2002-07-18T00:00:00",
"location_accuracy": "Within 5 metres",
"lake_boundary_id": null,
"geom_geojson": {
"type": "LineString",
"coordinates": [
[-79.6091428, 45.2161451],
[-79.6091436, 45.216149],
…
]
}
}
Tell buyers whether a lot has deep water for swimming and boating or a shallow, weedy shoreline. It is one of the first questions cottage buyers ask.
Draw depth lines on your own map and let anglers find drop-offs, shoals and basins.
Use contour lines with survey dates and accuracy as inputs to volume estimates and habitat-depth analysis, with provenance attached.
Find out how quickly water deepens off a shoreline before planning docks, boathouses or water intakes.
Every environmental layer shares the same API key, coordinate system and response conventions. Combine them in one integration.
Common questions about the Bathymetry Data API.
Bathymetry data describes the depth and shape of a lake bed. It is usually published as contour lines joining points of equal depth.
Depth is stored as metres below the water surface, so a contour 4 m down has a depth of −4. Use min_depth and max_depth with negative numbers, for example min_depth=-10&max_depth=0 for everything shallower than 10 m.
Ontario Ministry of Natural Resources bathymetry lines published through Ontario GeoHub. Surveys range from older hand-digitized transects to modern GPS surveys, and each line says which.
Ontario lakes that have been surveyed by the province. Coverage outside Ontario is not available today.
Fetch the lake from the Lake Data API and use its bounding box as the viewport for this API. Many lines are also linked directly by lake_boundary_id.
Request an API key from the dashboard or book a demo. Every request sends the key in the Api-Key header. Pricing is usage-based.
Neighbourly normalizes public open data into one schema. Source licences and attribution apply; see our terms.
Get an API key and query this layer today, or talk to us about coverage and volume.