Which external source can be used for public geospatial data besides GeoData.gov?

While ArcGIS Online is indeed a valuable resource for accessing a variety of geospatial data, the most suitable alternative external source for public geospatial data, besides GeoData.gov, is OpenStreetMap. OpenStreetMap is a collaborative mapping project that provides freely accessible geographic data across the globe, allowing users to contribute, update, and utilize mapping data for various applications.

OpenStreetMap serves as a significant source of public geospatial data due to its emphasis on community contributions and open licensing, which enhances its usability and accessibility. This project empowers users, from developers to researchers, to leverage vast amounts of crowd-sourced information for their own projects, making it an important resource for diverse geospatial analyses and applications.

USGS and NASA are also credible institutions providing public geospatial data but tend to focus on specific areas such as earth science, topography, and satellite imagery rather than the broad, user-generated mapping data that OpenStreetMap offers. ArcGIS Online, while it provides access to many datasets, operates within a framework that may not consistently offer the same level of open data accessibility that OpenStreetMap provides.