GeoExplorer teaching

Use your own Google account and registered Earth Engine project. No instructor authorization, shared password or test-user enrollment is required.

  1. Create or select your own Google Cloud project, register it for Earth Engine, and enable the Earth Engine API. Complete Google's applicable noncommercial eligibility or commercial registration requirements. Your account needs permission to use your project.
  2. Open GeoExplorer, enter your project ID (not its display name or number), and choose Google sign-in. Allow the popup and grant Earth Engine read-only permission.
  3. Start with a small rectangle and a short date range. Generate a map or retrieve monthly observations. Use coarser resolution for larger regions.
  4. Keep the tab open while processing. Download results before closing, reloading or signing out.

What runs where

Google Earth Engine evaluates satellite expressions with your account and project. Statistics and numerical clustering run in your browser using the local GeoExplorer scientific routines. Cloudflare serves static files. There is no instructor-owned computation server or credential fallback. The initial scientific-runtime download can take a moment.

Scientific methods and limits

MODIS MOD13Q1 retains SummaryQA 0–1 and applies the 0.0001 NDVI scale. Sentinel-2 uses B8/B4 NDVI, scene cloud percentage below 80, and excludes SCL 0, 1, 3, 8, 9, 10 and 11. CHIRPS monthly rainfall is a sum of daily precipitation in mm; NDVI monthly composites are arithmetic means. Monthly time-series retrieval uses full calendar months intersecting the selected range, matching the local implementation.

Regional extraction uses EPSG:4326 at the selected scale. Sentinel-2 clustering uses a fixed EPSG:3857 grid, complete cases, robust monthly median/IQR scaling with the existing fallback, and GeoExplorer's Bayesian MAP-EM, classic PAM, CLARA or SOM/Ward routines. Stability compares runs on an anchored EPSG:6933 common grid with exact label matching. Stability measures sensitivity, not classification accuracy.

The optional SPAM 2020 v2r2 mask is the same public teaching asset used by SoilExplorer. Its native 5-arc-minute cells are thresholded with nearest-neighbour lookup. Coverage threshold zero means strictly positive coverage; other thresholds are inclusive. Optional intensity thresholds are inclusive; -9999 is excluded. It masks training samples and predictions for all methods and stability runs. It is not an NDVI variable, and sample shares are not cropped hectares.

Spatial anomalies use same-calendar-month composites within the observation period. The legacy baseline-year fields do not change that calculation. Tabular standardized anomalies use sample standard deviation of the supplied observations. Temporal aggregation remains an arithmetic mean, including rainfall, as in the local application.

Downloads and differences from the manual

Download the unchanged local PDF user manual · Illustrated manual · Student README.txt

The PDF describes the native/private hosted editions too. This standalone edition uses direct monthly computation instead of durable batch exports. There are no shared owner/collaborator accounts, instructor quotas, 30-day server storage, or restart recovery. Your Google project quotas apply. Cancel stops further retrieval; a Google request already in progress may finish. Closing or reloading loses in-memory results. Large analyses can reach interactive Earth Engine limits; reduce area, time range or resolution.

Troubleshooting

If sign-in succeeds but initialization fails, verify the chosen project's Earth Engine registration, enabled API and account permissions. If a school account is blocked, consult its Workspace administrator. Google can require app verification for sensitive scopes; In production alone does not remove verification warnings or user caps. Never send access tokens in support messages.

Earth Engine authentication and scopes · Privacy · Open GeoExplorer