Earth Engine app

Versión en español

Earth Engine app

https://ee-ugr-default-project.projects.earthengine.app/view/monitoreo

The MonitorEO app is used in the browser: there is nothing to install and no need for an Earth Engine account, because it computes with the Google Cloud project of MonitorEO. It has almost everything of the QGIS plugin: maps, time series, trends, comparison of periods and burn severity, with the same variables, filters and options (see Concepts). It gives the same results as the Python package: the same computation in both tools gives the same values (the tests of the repository check it).

It opens in English; the button Español / English (top right of the panel) switches the language.

The panel

From top to bottom:

• Region: a Protected area (WDPA) (type part of the name, Search and choose it; large ones take a few seconds to load), the Ecoregion of RESOLVE 2017 where you click on the map, the Map view or a Drawn polygon (one click per vertex and double-click to close it). Below, its area is shown.
• Variable: variable, sensor, pixel and collection; below, its name, unit, dates and formula.
• Period (YYYY-MM-DD), with two boxes: Only this season of each year (MM-DD) and Compare with another period.
• Remove pixels with: the filters for clouds and shadows, water, snow and aerosols. When you choose a variable, the ones that remove what it measures are unchecked (water with the NDWI, snow with the NDSI).
• Map: Metric, Temporal aggregation (Whole period, Each year, then between years...) and Add to the map.
• Time series: Step, Metric of each step, Statistic of the region and Compute the time series. With Compare with another period checked, it compares the two periods by month, 16 days or year.
• Trends (Mann-Kendall and Sen): Trend table of the region and Trend map of a part of the year (Part of the year of the map; Sen's slope, τ, Z, p-value, initial value or years with data).
• Burn severity of a fire (dNBR or RBR): Sensor, Index and periods Before the fire and After the fire; Compute the severity gives the map of the USGS classes and the area of each one with the dNBR, or the continuous map of the RBR and its statistics (see Concepts).
• About MonitorEO: funding, How to cite and links.

The results appear in a panel to the right of the map: the chart, the table and the buttons Download CSV and Download GeoTIFF, which prepare a download link. The GeoTIFF is in the UTM projection of the region, with NoData -9999, and with larger pixels than those of the data if the region is large. The ⤢ button of a chart opens it in another tab, from where it can be downloaded as an image.

Limits

All the users of the app share the monthly computing quota of the MonitorEO project, so each request has a maximum size:

Region	up to 100,000 km²
Sentinel-2	regions of up to 5,000 km² (larger: Landsat or MODIS)
Series, trends and comparisons	up to 400 steps (e.g. 33 years with a monthly step)
GeoTIFF	about 32 MB: in large regions, with larger pixels

For what the app does not do, use the QGIS plugin or the Python package with your own account: regions from your layers or files, exports to Google Drive, GeoTIFF at the resolution of the data in large regions, recipes of variables for models and longer series.

For administrators

The code is in the gee folder of the repository: core.js (the core of the Python package in JavaScript), ui.js (the panel) and build.py, which writes monitoreo_app.js, the single script of the app, with the catalog and the texts of the package. To publish a new version:

1. python gee/build.py --project ee-ugr-default-project (after changing core.js, ui.js, catalog.json or about.py).
2. EE_PROJECT=ee-ugr-default-project pytest tests/test_gee.py (with npm install in gee): compares the app with the Python package in the same cases.
3. Paste monitoreo_app.js in a new script of the Code Editor, with the account of the project, and in Apps, the pencil of MonitorEO > source code: Current contents of editor > Update.

The limits of the table are at the top of ui.js (LIMITS).