West Coast Whales
iNaturalist Humpback Whale Observations Along the Pacific Coast of the Americas
This map was an opportunity to explore iNaturalist data in the ArcGIS Living Atlas and challenge myself with a new data source. Humpback whales, well documented and strongly migratory, provided a dataset with enough volume and structure to reveal meaningful spatial patterns along the west coast.
The intended audience is the general public and GIS enthusiasts, though researchers may also find it useful as a reference. The data was left largely unadjusted to preserve the character of the original observations, with only research-grade records included. A diverging color scheme emphasizes north–south distribution, using red for northern sightings and blue for southern, while a dark basemap helps the observations stand out clearly.
The coastal distribution of points created a challenging layout. Large areas of negative space pushed the design toward a rotated view and the use of an unprojected coordinate system to keep the composition clean. Despite these constraints, seasonal patterns emerged clearly in the monthly sighting charts. Whether those peaks reflect whale presence or increased whale-watching activity is uncertain, highlighting an important limitation of crowdsourced data.
The map demonstrates both the strengths and caveats of citizen science observations. It offers a clear, accessible view of whale distribution and seasonality while showing how iNaturalist data can be used effectively within GIS workflows, even when working with complex coastal geometries.
2024-10-23