Description

Cons 127 Observing the Earth from Space

Lab 5: Detecting Change with NDVI: Vegetation Responses through the Spectrum.

Total marks possible: 29

Instructor: Prof. Nicholas Coops

Office: FSC 2301

604 822 6452

nicholas.coops@ubc.ca

TA: Dave Williams

Office: FSC 2232

Dave.Williams@forestry.ubc.ca

For this assignment you will...

 Learn about the spectral responses of vegetation

 Learn how to calculate and utilize the Normalized Difference Vegetation Index (NDVI)

 Be introduced to analyses of land cover, land use patterns, and land cover change

 Explore how humans are impacting terrestrial ecosystems

Submit the following in a report:

 Answers to questions 1 through 8. Brevity is much appreciated!

 When answering these questions, you DO need to cite your references and put answers into

your own words. (2 marks)

This lab requires a computer with an internet connection, and the Java Web Application, which you used

in Lab 4 (but can be downloaded here). If Google Chrome is your default browser you’ll need to switch

to Internet Explorer if using Windows, or Safari if using a Mac OS. If you have any outstanding issues

running Java talk to the TA to set up a time to complete the lab on a Forestry computer.

Part 1: Interpreting Change using ESRI Change Matters

1. Understanding how Earth systems change through time, either due to natural or anthropogenic

processes (or both!), is an integral part of understanding how the world around us operates, how it

affects us, and how humanity impacts the natural world. With increasing data availability and

abundance, newer and better sensors and satellite constellations, and an increasingly long timeline

of observations, remote sensing scientists are well-positioned to detect change on the Earth at

many resolutions – in time, space and the EM spectrum. Satellite sensors provide consistent and

repeatable measurements of everything from whole-earth phenomena, like global primary

productivity maps derived from MODIS data, to sub-metre imagery of the trees lining city streets.

2. One common way of remotely sensing change on the Earth’s surface is by analyzing vegetation

through time – its spatial patterns and abundance, as well as its spectral properties. Because

vegetation reflects NIR wavelengths strongly (remember the red edge from lecture), remote sensing

scientists have developed vegetation indices, the most well-known of which is probably the

Normalized Difference Vegetation Index (NDVI), that take advantage of vegetation’s spectral

qualities. Using spectral vegetation indices we can directly and quantitatively compare remotely

sensed images. Vegetation indices also allow us to assess plant health and vigour, and can be

combined with other information to, for example, assess how surface temperatures are changing

due to the expansion of Indonesian oil palm plantations (Ramdani, Moffiet, & Hino, 2014), or study

how cities grow and change.

Q1. What is the formula for the NDVI (1)? Which Landsat bands are used to calculate the NDVI (1)?

3. In a web browser You’ll initially be

shown three false-colour images of Mount St. Helens: one in 1975, one in 2000, and one showing

the NDVI change between the first two images. To the top-right of the images is a “View Larger” link

that you might want to click, though note that it may cause the three images’ views to become

disconnected.