https://sites.google.com/view/tab-inventories/2022/2022-tlef/mapping-change

One of the most powerful ways to help your community understand the changes that we are seeing from human activities (for example, damming rivers, mining, urban development, agriculture) and climate change, is to create visualizations from satellite and aerial imagery over time. We will explore two free tools that can be used; the timeslider in Google Earth Pro and tools built on the Google Earth Engine platform (Timelapse, Global Forest Watch, etc.). The hands-on activities will provide you with map visualizations of environmental change that you can use in your own work.

Our breakout room expert will be Annie Taylor, who can help you with the Earth Engine platform, a powerful tool for accessing historic satellite imagery and conducting analyses of landuse/land cover changes over time. Even if you are not a coder, you can watch a demonstration of Earth Engine and learn the technology behind the tools we will be using in the main session.

Examples of Google Earth Engine analyses in support of Canadian First Nations land concerns

• Deforestation in Hul’qumi’num territory between 2000 and 2014 analyzed using Earth Engine and imported for display in Google My Maps click here

• Analysis of night light data between 1999 and 2013 using Earth Engine was used as proxy measure for urban density and a secondary measure of urban expansion impacting Hul'qumi'num peoples historical and cultural sites. Results displayed in Google My Maps click here

• Caring for Lhulq’us (pryopia spp.): mapping and remote sensing of Hul’quimi’num culturally important seaweeds in the Salish Sea

Our first activity will use tools built on the Google Earth Engine platform to help us to visualize changes in satellite imagery over time. Using Timelapse and the Timelapse layer in Google Earth Web we can watch an animation of changes over time. Then we will use Global Forest Watch, which uses Earth Engine technology to compare pixels between satellite images from different dates to highlight tree loss and tree gain. Forest Watch has a suite of analytical tools that create graphs and reports that we can use to examine changes in forest cover from 2001 to 2021. Global Forest Watch is a user friendly interface that will introduce you to the type of work you can do in the Earth Engine platform.

1. Go to Google Timelapse click here

2. Look at the examples that they give you in the gallery

3. Search for your community, zoom in and out, change the speed of the animation

1. Go to Global Forest Watch click here

2. Search for your community

3. Use the tools and layers to examine forest cover loss and gain in your community

This is a Global Forest Watch analysis of forest cover change in Lake County, California

For our second hands-on activity we will use the timeslider in Google Earth Pro to change the imagery layer to specified dates. Timeslider includes both satellite and aerial imagery; satellite imagery goes back to 1984, and in some location, aerial imagery is available all the way back to the 1930's.

Time slider in Google Earth Pro to access historic imagery

Image Overlay in Google Earth Pro