How to calculate forest loss in Google Earth Engine?

How to calculate forest loss in Google Earth Engine?

In this section, we’ll compare the total amount of forest loss that happened within the Congo Republic in the year 2012 to the amount of forest loss that happened within the country’s protected areas at the same time. As you learned in the Earth Engine API tutorial, the key method for calculating statistics in an image region is reduceRegion ().

How to calculate statistics in Google Earth Engine?

As you learned in the Earth Engine API tutorial, the key method for calculating statistics in an image region is reduceRegion (). ( Learn more about reducing image regions .) For example, suppose we want to calculate the number of pixels estimated to represent forest loss during the study period. For that purpose, consider the following code:

What are geometric operations in Google Earth Engine?

Geometric Operations Earth Engine supports a wide variety of operations on Geometry objects. These include operations on individual geometries such as computing a buffer, centroid, bounding box, perimeter, convex hull, etc.

How to calculate tree cover in Google Earth?

Calculate the tree cover area (ha). Use pixelArea () to get the value of each pixel in square metres, divide by 10,000 to convert to hectare, and sum over the result for a measure of area. 6. Calculate the actual average minimum forest area used (ha).

How do you calculate area in Earth Engine?

To help compute areas, Earth Engine has the ee.Image.pixelArea () method which generates an image in which the value of each pixel is the pixel’s area in square meters. Multiplying the loss image with this area image and then summing over the result gives us a measure of area:

How to calculate the area of an image in Google Earth?

There are a couple of ways to calculate the area of the image in the Google Earth Engine. The full implementation of both method can be accessed using this link. We can calculate the area of the image by counting the total number of unmasked pixels in that image.

How many hectares of forest are lost per year?

The establishment of forest plantations (2.7 million hectares per year) partially offset the loss of natural forests, resulting in a net loss of total forests of about 1.6 million hectares (just under 1 percent) per year. 34 Overall loss of FOWL in the region was about 0.8 million hectares per year during the period.

What’s the result of Forest lost in Excel?

By expanding the object printed to the console, observe that the result is 4897933 pixels of forest lost. You can clean up the printout in the console a bit by labeling the output and getting the result of interest from the dictionary returned by reduceRegion ():

How to display forest loss and gain in Arkansas?

Pixels with forest loss and gain in Arkansas. Combining this example with the result from the previous section, it’s now possible to recreate the figure from the beginning of the tutorial: // Displaying forest, loss, gain, and pixels where both loss and gain occur.

How big is the global forest change data?

The Hansen et al. (2013) Global Forest Change dataset in Earth Engine represents forest change, at 30 meters resolution, globally, between 2000 and 2014. Let’s start by adding the Hansen et al. data to the map.

How to import Hansen et al global forest change data?

Either import the global forest change data ( learn more about searching and importing datasets ) by searching for “Hansen forest” and naming the import gfc2014, or copy the following code into the Code Editor: Click on the Run button at the top of the Code Editor and you should see something like Figure 1. Figure 1.