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Last updated October 20th 2020

Global Forest Watch Help Center

https://www.globalforestwatch.org/help

Investigate forest change with recent satellite imagery

The recent satellite imagery tool provides information regarding vegetation health around the world and can help validate near real-time alerts. New images are populated daily, showing the latest satellite imagery from the Sentinel-2 and Landsat 8 systems.

The imagery offers global geographic coverage at a 10 x 10-meter resolution with Sentinel-2, and a 30 x 30-meter resolution with Landsat 8. The Sentinel-2 satellite revisits locations every 10 days, while Landsat 8 revisits locations every 16 days.

Another resource to help validate near real-time alerts is the 5-meter resolution Planet imagery. The Planet imagery basemap is updated monthly and is available for the tropics. Learn more about the Planet basemap and other available basemaps here.

Recent satellite imagery features

Recent satellite imagery can help show what an area looks like in near real-time and facilitate validation of forest change data, such as deforestation or fire alerts.

  1. To use the recent satellite imagery tool, situate the crosshair in the center of the map over your area of interest then click the satellite icon on the bottom right to activate it. The tool will only work if the crosshair is situated above land. For the best results, zoom in to a specific location before activating the tool.
Zoom in to the location you’d like to investigate with recent satellite imagery.
Click the satellite icon to activate the tool.
  1. The “Acquisition Date” drop-down menu at the top of the pop-up window allows you to access images 1 week, 2 weeks, 4 weeks, 2 months, 3 months, 6 months or 12 months before a specified date. The default acquisition date will be 3 months before the present date, but can be changed by clicking on the date.
  2. Adjust the cloud cover percentage by clicking and dragging the bar to the desired percentage. The default is set at 25%, which means only satellite imagery with less than 25% cloud cover will load. The higher the maximum cloud cover percentage, the more images will appear in your search; however, some of these images may be obscured by clouds.
  3. There are two imagery options available: natural color or vegetation health. The natural color imagery uses information from visible light (red, green and blue) to show Earth’s surface as it would appear to the human eye. The vegetation health imagery is detected using the Normalized Difference Vegetation Index (NDVI), which uses information from both red and near-infrared reflectance. The NDVI method relies on the fact that healthy vegetation absorbs most visible light and reflects most near-infrared light that strikes its surface. When interpreting imagery that shows vegetation health, red indicates healthy growing vegetation, green indicates bare ground and black/purple indicates water bodies. While the natural color imagery is more intuitive, some details can be lost as images can be hazy and subtle features can be difficult to recognize. By contrast, the vegetation health imagery highlights differences in land cover and can make the images easier to interpret.
Select “Natural color” to view imagery from visible light, displaying the Earth’s surface as it would appear to the human eye.
Select “Vegetation Health” to view imagery from NDVI. The red/orange colors reflect healthy vegetation, whereas the green color reflects bare ground. The black/purple colors reflect water bodies.

Use the recent satellite imagery tool

  1. Let’s say you are managing this area in the Democratic Republic of Congo. In this example, you can see how the deforestation alerts align with the brown – or cleared – areas in the natural color satellite imagery.
Activate recent satellite imagery over the area you’d like to investigate. The deforestation alerts and satellite imagery indicate tree cover loss based on the brown clearing zones beneath the alerts.
  1. The deforestation alerts are activated for April 1st, 2020 through May 16th, 2020. This shows locations of potential deforestation for that time period.
  2. To investigate further, recent satellite imagery within the past four weeks was selected. The maximum cloud cover percentage was lowered and “natural color” was selected for the images. This will help you get started in verifying whether the alerts indicate any clearings.
  3. The deforestation alert opacity was reduced in order to see a clearer satellite image beneath the alerts. Learn more about how to reduce data layer opacity here. In the example below, there is evidence of clearings throughout this area based on the brown areas where the alerts are.
Reduce the deforestation alert opacity to help reveal more of the underlying recent satellite images.
  1. Zooming in closer to the area can also provide a clearer view of the characteristics of the clearing, helping to determine whether the clearing is from human or natural causes, as well as what the likely driver of the clearing was (e.g., small-holder agriculture, commercial agriculture, mining, logging, fire, etc.).
  2. To investigate and verify further, you can activate the vegetation health imagery. Here, the alerts are overlaid on green patches, indicating bare ground – you can now verify that clearing has occurred in this area.
Activate the vegetation health imagery to help identify areas of likely tree cover loss. The green patches indicate bare ground and likely clearing.
  1. From here, you can begin taking the necessary steps to investigate on the ground and take appropriate action. Learn more about how the Forest Watcher mobile app can help you investigate forest change while offline and in the field here.

In short, recent satellite imagery is a powerful tool to help monitor, verify and investigate an area of interest before heading into the field. Identifying whether tree cover loss has occurred before investigating on the ground can save you time, money and other resources and allow you to focus your efforts on where forest threats are actually occurring. Additionally, it can be used in reports, policy briefs, presentations and throughout the media to show where deforestation has likely occurred and its likely cause.

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Last updated October 20th 2020

Global Forest Watch Help Center

https://www.globalforestwatch.org/help

Investigate forest change with recent satellite imagery

The recent satellite imagery tool provides information regarding vegetation health around the world and can help validate near real-time alerts. New images are populated daily, showing the latest satellite imagery from the Sentinel-2 and Landsat 8 systems.

The imagery offers global geographic coverage at a 10 x 10-meter resolution with Sentinel-2, and a 30 x 30-meter resolution with Landsat 8. The Sentinel-2 satellite revisits locations every 10 days, while Landsat 8 revisits locations every 16 days.

Another resource to help validate near real-time alerts is the 5-meter resolution Planet imagery. The Planet imagery basemap is updated monthly and is available for the tropics. Learn more about the Planet basemap and other available basemaps here.

Recent satellite imagery features

Recent satellite imagery can help show what an area looks like in near real-time and facilitate validation of forest change data, such as deforestation or fire alerts.

  1. To use the recent satellite imagery tool, situate the crosshair in the center of the map over your area of interest then click the satellite icon on the bottom right to activate it. The tool will only work if the crosshair is situated above land. For the best results, zoom in to a specific location before activating the tool.
Zoom in to the location you’d like to investigate with recent satellite imagery.
Click the satellite icon to activate the tool.
  1. The “Acquisition Date” drop-down menu at the top of the pop-up window allows you to access images 1 week, 2 weeks, 4 weeks, 2 months, 3 months, 6 months or 12 months before a specified date. The default acquisition date will be 3 months before the present date, but can be changed by clicking on the date.
  2. Adjust the cloud cover percentage by clicking and dragging the bar to the desired percentage. The default is set at 25%, which means only satellite imagery with less than 25% cloud cover will load. The higher the maximum cloud cover percentage, the more images will appear in your search; however, some of these images may be obscured by clouds.
  3. There are two imagery options available: natural color or vegetation health. The natural color imagery uses information from visible light (red, green and blue) to show Earth’s surface as it would appear to the human eye. The vegetation health imagery is detected using the Normalized Difference Vegetation Index (NDVI), which uses information from both red and near-infrared reflectance. The NDVI method relies on the fact that healthy vegetation absorbs most visible light and reflects most near-infrared light that strikes its surface. When interpreting imagery that shows vegetation health, red indicates healthy growing vegetation, green indicates bare ground and black/purple indicates water bodies. While the natural color imagery is more intuitive, some details can be lost as images can be hazy and subtle features can be difficult to recognize. By contrast, the vegetation health imagery highlights differences in land cover and can make the images easier to interpret.
Select “Natural color” to view imagery from visible light, displaying the Earth’s surface as it would appear to the human eye.
Select “Vegetation Health” to view imagery from NDVI. The red/orange colors reflect healthy vegetation, whereas the green color reflects bare ground. The black/purple colors reflect water bodies.

Use the recent satellite imagery tool

  1. Let’s say you are managing this area in the Democratic Republic of Congo. In this example, you can see how the deforestation alerts align with the brown – or cleared – areas in the natural color satellite imagery.
Activate recent satellite imagery over the area you’d like to investigate. The deforestation alerts and satellite imagery indicate tree cover loss based on the brown clearing zones beneath the alerts.
  1. The deforestation alerts are activated for April 1st, 2020 through May 16th, 2020. This shows locations of potential deforestation for that time period.
  2. To investigate further, recent satellite imagery within the past four weeks was selected. The maximum cloud cover percentage was lowered and “natural color” was selected for the images. This will help you get started in verifying whether the alerts indicate any clearings.
  3. The deforestation alert opacity was reduced in order to see a clearer satellite image beneath the alerts. Learn more about how to reduce data layer opacity here. In the example below, there is evidence of clearings throughout this area based on the brown areas where the alerts are.
Reduce the deforestation alert opacity to help reveal more of the underlying recent satellite images.
  1. Zooming in closer to the area can also provide a clearer view of the characteristics of the clearing, helping to determine whether the clearing is from human or natural causes, as well as what the likely driver of the clearing was (e.g., small-holder agriculture, commercial agriculture, mining, logging, fire, etc.).
  2. To investigate and verify further, you can activate the vegetation health imagery. Here, the alerts are overlaid on green patches, indicating bare ground – you can now verify that clearing has occurred in this area.
Activate the vegetation health imagery to help identify areas of likely tree cover loss. The green patches indicate bare ground and likely clearing.
  1. From here, you can begin taking the necessary steps to investigate on the ground and take appropriate action. Learn more about how the Forest Watcher mobile app can help you investigate forest change while offline and in the field here.

In short, recent satellite imagery is a powerful tool to help monitor, verify and investigate an area of interest before heading into the field. Identifying whether tree cover loss has occurred before investigating on the ground can save you time, money and other resources and allow you to focus your efforts on where forest threats are actually occurring. Additionally, it can be used in reports, policy briefs, presentations and throughout the media to show where deforestation has likely occurred and its likely cause.

Print this article

Investigate forest change with recent satellite imagery

The recent satellite imagery tool provides information regarding vegetation health around the world and can help validate near real-time alerts. New images are populated daily, showing the latest satellite imagery from the Sentinel-2 and Landsat 8 systems.

The imagery offers global geographic coverage at a 10 x 10-meter resolution with Sentinel-2, and a 30 x 30-meter resolution with Landsat 8. The Sentinel-2 satellite revisits locations every 10 days, while Landsat 8 revisits locations every 16 days.

Another resource to help validate near real-time alerts is the 5-meter resolution Planet imagery. The Planet imagery basemap is updated monthly and is available for the tropics. Learn more about the Planet basemap and other available basemaps here.

Recent satellite imagery features

Recent satellite imagery can help show what an area looks like in near real-time and facilitate validation of forest change data, such as deforestation or fire alerts.

  1. To use the recent satellite imagery tool, situate the crosshair in the center of the map over your area of interest then click the satellite icon on the bottom right to activate it. The tool will only work if the crosshair is situated above land. For the best results, zoom in to a specific location before activating the tool.
Zoom in to the location you’d like to investigate with recent satellite imagery.
Click the satellite icon to activate the tool.
  1. The “Acquisition Date” drop-down menu at the top of the pop-up window allows you to access images 1 week, 2 weeks, 4 weeks, 2 months, 3 months, 6 months or 12 months before a specified date. The default acquisition date will be 3 months before the present date, but can be changed by clicking on the date.
  2. Adjust the cloud cover percentage by clicking and dragging the bar to the desired percentage. The default is set at 25%, which means only satellite imagery with less than 25% cloud cover will load. The higher the maximum cloud cover percentage, the more images will appear in your search; however, some of these images may be obscured by clouds.
  3. There are two imagery options available: natural color or vegetation health. The natural color imagery uses information from visible light (red, green and blue) to show Earth’s surface as it would appear to the human eye. The vegetation health imagery is detected using the Normalized Difference Vegetation Index (NDVI), which uses information from both red and near-infrared reflectance. The NDVI method relies on the fact that healthy vegetation absorbs most visible light and reflects most near-infrared light that strikes its surface. When interpreting imagery that shows vegetation health, red indicates healthy growing vegetation, green indicates bare ground and black/purple indicates water bodies. While the natural color imagery is more intuitive, some details can be lost as images can be hazy and subtle features can be difficult to recognize. By contrast, the vegetation health imagery highlights differences in land cover and can make the images easier to interpret.
Select “Natural color” to view imagery from visible light, displaying the Earth’s surface as it would appear to the human eye.
Select “Vegetation Health” to view imagery from NDVI. The red/orange colors reflect healthy vegetation, whereas the green color reflects bare ground. The black/purple colors reflect water bodies.

Use the recent satellite imagery tool

  1. Let’s say you are managing this area in the Democratic Republic of Congo. In this example, you can see how the deforestation alerts align with the brown – or cleared – areas in the natural color satellite imagery.
Activate recent satellite imagery over the area you’d like to investigate. The deforestation alerts and satellite imagery indicate tree cover loss based on the brown clearing zones beneath the alerts.
  1. The deforestation alerts are activated for April 1st, 2020 through May 16th, 2020. This shows locations of potential deforestation for that time period.
  2. To investigate further, recent satellite imagery within the past four weeks was selected. The maximum cloud cover percentage was lowered and “natural color” was selected for the images. This will help you get started in verifying whether the alerts indicate any clearings.
  3. The deforestation alert opacity was reduced in order to see a clearer satellite image beneath the alerts. Learn more about how to reduce data layer opacity here. In the example below, there is evidence of clearings throughout this area based on the brown areas where the alerts are.
Reduce the deforestation alert opacity to help reveal more of the underlying recent satellite images.
  1. Zooming in closer to the area can also provide a clearer view of the characteristics of the clearing, helping to determine whether the clearing is from human or natural causes, as well as what the likely driver of the clearing was (e.g., small-holder agriculture, commercial agriculture, mining, logging, fire, etc.).
  2. To investigate and verify further, you can activate the vegetation health imagery. Here, the alerts are overlaid on green patches, indicating bare ground – you can now verify that clearing has occurred in this area.
Activate the vegetation health imagery to help identify areas of likely tree cover loss. The green patches indicate bare ground and likely clearing.
  1. From here, you can begin taking the necessary steps to investigate on the ground and take appropriate action. Learn more about how the Forest Watcher mobile app can help you investigate forest change while offline and in the field here.

In short, recent satellite imagery is a powerful tool to help monitor, verify and investigate an area of interest before heading into the field. Identifying whether tree cover loss has occurred before investigating on the ground can save you time, money and other resources and allow you to focus your efforts on where forest threats are actually occurring. Additionally, it can be used in reports, policy briefs, presentations and throughout the media to show where deforestation has likely occurred and its likely cause.

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