[On hold] Mark previously detected features as active or inactive

[rudokemper]

Several of our users have indicated that the current change detection methodology, while helpful for showing new areas caused by forest cover loss, does not inform us about the status of an activity once detected. For example, once a new mining site has been cleared, the site could remain active for years. Or, an old logging road may be opened up again for another round of timber harvesting.

Currently, we are not providing any information about these kinds of dynamics, but our users are telling us that this information is just as important as new alerts. Additionally, the way we currently create a distinction between "most recent alerts" (with pulsing circles as a visual cue to draw the user's attention to these first and foremost) and "previous alerts" risks giving the impression that existing activity in previously alerted areas is not as concerning as the most recent ones.

There are a few issues at stake here:

1. Can we work with our alerts provider to provide more information on the status of alerts once reported? I can imagine that they could use NDVI and other spectral data to analyze all alerts at regular intervals to detect any changes in the respective activity. For example, for a logging road that is no longer in use, we might expect that vegetation would continue to grow again, hence a change in the NDVI index. Or for an alluvial mining area that is still in use, we could use the lack of vegetation regrowth or the presence of soil disturbance as indicators. They could then add a status property to each alert GeoJSON. Perhaps it could be a distinction between "active" and "inactive" to start with, but it could also be interesting to report on things like "recovered" or "irrevocably altered" (@mmckown mentioned a better term, but I can't remember it).
2. For guardianconnector-views, we need to consider a different approach to visual hierarchy to ensure that ongoing activities in previously alerted areas are not overlooked, using the proposed status property. This might involve splitting the current "previous alerts" layer into two, so we could have three layers in total, with different styling. Maybe something like:
   • Newly Detected Alerts - For newly detected activities or changes; what is currently called "most recent alerts".
   • Active Alerts - For areas with ongoing or recurrent activities.
   • Inactive Alerts - For areas where activities have ceased, and natural regrowth or stabilization (or simply cessation of detectable activity) is observed.

I think we will first have to discuss (1) with our alerts provider before taking any action on this for GCV. This may need to be scoped for a future iteration of funded work for them.

[rudokemper]

Exploring (1) using visual (RGB) imagery from Sentinel-2 (but there will be spectral data available to do this analytically):

Active mining:

Inactive mining:

Active road:

Inactive road:

[rudokemper]

We have now discussed this issue with our alerts provider and one of our users.

To proceed on this issue in terms of development work on GCV, we will need to wait until we know more about changes to the alerts outputs from the alerts provider. So I am putting this issue on hold.