Data Sources
Modern imagery ecosystems and open geospatial infrastructure.
Sentinel-2
What Sentinel-2's bands, revisit, and processing levels are good for, the processing changes that affect time series, and where to get the data.
Landsat
Why Landsat's multi-decade archive matters, what its instrument generations change, and how to build a comparable long record from it.
NAIP
Where high-detail NAIP aerial imagery fits among satellite sources, what its acquisition cycle and uncalibrated values mean for analysis, and how to use it for reference and validation.
DEMs
What a digital elevation model represents, which quality issues shape terrain analysis, and how to choose among global and national elevation models.
STAC Catalogs
How the SpatioTemporal Asset Catalog's object model, search APIs, and signed assets let you find and select imagery the same way across providers.
Microsoft Planetary Computer
The Planetary Computer as an open STAC catalog over cloud-hosted data: what it provides now that its hosted notebooks are retired, and how signed access shapes workflows.
Open Geospatial Data
How to judge whether an open geospatial dataset is fit for use: licensing, provider types, common integration risks, and a repeatable checklist.