Digital Earth Watch

The Digital Earth Watch (DEW) project grew from a NASA grant project titled Measuring Vegetation Health. Its goal was to teach about how monitoring the health of vegetation can be done at various scales: from individual plants to large scale ecosystems. See Overview.

DEW logo


1. Digital Image Basics1.1 How Is Light Created?
1.2 LEDs As Light Sensors
1.3 Newsprint and Video Displays
1.4 Creating Colors
1.5 Dueling Beams of Light
1.6 Resolution and Pixel Color
1 Circle from 3
Cat’s True Colors
2. Measuring With Digital Images2.1 Spatial Analysis: Length
2.2 Spatial Analysis: Area
2.3 Color in Surface Features
2.4 Take the Best Digital Photos
2.5 What Parent Do You Look Like?
Disappearing Sea
3. Analyzing Plants and Ecosystems3.1 Observe Changing Vegetation
(Adopt-a-Leaf/Branch & PicturePost)
3.2 In Your Backyard
3.3 Changes in Mt. St. Helens
3.4 IR Vision
3.5 Plant Stress Detector
How Tall is the Tree?
Tree Diameter
Pine Needle Length
Tree Canopy Growth
Leaf Area
Plants Grow At Night?
4. Monitoring Earth Systems4.1 Aerial Photography
4.2 The View from 400 Miles Up
4.3 Get Earth Images
Appendices:DEW Partners
Concept Mapping
DEW Formative Evaluation
DEW Program Evaluation
The Future of DEW

DEW software for DEW Investigations

All Images for DEW Investigations (.zip file)


Sensors capturing digital images provide crucial data at all scales, from smart phones to Earth orbiting satellites that have provided stunning pictures of the Earth for decades. Those images have transformed people’s vision of their home planet and have enabled us to study Earth processes in ways that were not possible prior to the space age, thus creating a new field, known as Earth Systems Science. Underlying a mastery of the capture and analysis of digital images is an understanding of vision, light, and color.