A Mask is a rule that keeps or hides pixels by thresholding the values of one or more insights. “Keep only where NDWI ≥ 0.2” is a water mask; “hide where a cloud score is high” is a cloud mask. Apply a mask and it filters every layer you render, so you analyze only the pixels that matter.
Masks are not the same as Zones. A Zone is a polygon you draw inside an Area (see Zones, Geochemical & Geophysical Data); a Mask is a spectral rule driven by insight values. Both can hide parts of an image, but a Zone masks by location and a Mask masks by what the pixels are.
Two kinds of mask #
- Predefined masks — platform-provided masks (cloud, cloud-shadow, water, snow, bare-ground and the like). They’re ready to use on every account; you can select them but not edit or delete them. The exact set depends on your instruments.
- Your masks — masks you create for your own work. You can edit, delete and share them with teammates (shared teammates get view-only access).
What a mask is made of #
- Name and a color (the color is used when you display the mask as an overlay).
- One or more insights, each with a Min and/or Max threshold. The range you set is the range that’s kept — the feature of interest. When a mask has several insights, a pixel must satisfy all of them to pass (the conditions are combined).
- Compatible instruments — worked out automatically: a mask can run only on instruments that can compute every insight it uses. You never pick the instruments; the platform derives them and quietly skips the mask on any imagery that can’t support it.
Creating a mask #
There are two ways to create one.
From the Masks panel — like Areas, Stacks and Insights, the Masks panel in the left rail has a ＋ New button (New mask) that opens the mask editor:
- General — the mask name and an optional description.
- Appearance — the mask color (a swatch picker or a hex value).
- Insights & thresholds — Add Insight to include an insight, each with its Min Threshold / Max Threshold; add as many as you need. At least one threshold value is required per insight, and Min can’t exceed Max.
- Compatible instruments — a live readout of which of your instruments the mask can run on, given the insights you’ve chosen.
Save with Create Mask. The description is kept as an automatic summary of the thresholds, so it always reads true. (Editing an existing mask opens the same editor via its Edit action.)
From a threshold on the map — the quickest path when you’re already looking at a result:
- Render a single-band insight on the Globe and open its Threshold tool.
- Set the Min / Max that isolate your feature — you can see the effect on the map as you adjust.
- Click Save Mask Threshold. In the Save Mask dialog, either give a new mask a name and color, or add this threshold to an existing mask.
Either way the mask is saved with its insight(s) and thresholds, ready to apply. To build a multi-condition mask, start from either path and keep adding insight-thresholds in the editor.
Managing your masks #
The Masks panel lists your masks with a search box and filters (by instrument, and by access). Each mask’s actions menu offers Details (a read-only view — see Applying Masks & Masking Modes), Edit, Share, and Delete. Predefined (platform) masks and masks shared to you are view-only.
Once you have masks, the next step is switching them on and choosing how they render — see Applying Masks & Masking Modes.