S CIENCE TECHNOLOGY LESSON 5

REVIEW Electromagnetic Spectrum (definition): The range of energy which contains parts or bands: visible light, infrared, ultraviolet, microwave (radar), gamma ray, x-ray and radio. Different parts of the EM Spectrum have different wavelengths and frequencies.

R EVIEW C ONT. Pixels (definition): The smallest unit of a digital picture. Satellite images are made up of a matrix of many pixels each with its own value. Colors represent the reflected light energy.

G ROUND T RUTHING – B ALTIMORE, MD

IMAGE INTERPRETATION Compare this satellite image to the view from an airplane window – write in notebook List visual clues that help identify different kinds of land cover. Hint: geometric shapes usually indicate human-made areas. Image interpretation is the initial stage of land cover mapping Remember ground truthing is a technique that uses field observations to determine the accuracy of a land cover map made from a satellite image.

C OLOR CODE TO IMAGE INTERPRETATION Red: vegetation with high photosynthetic activity (growing grass or trees in full leaf) Orange: Vegetation that is not currently photosyntheticaly active, lawns Green: deciduous forest areas Blue/Purple: concrete, roads, cities, other impervious surfaces Blue/Black: water Burnt/Brownish Orange: mix of deciduous trees and lawns; suburban areas

A CTIVITY : G ROUND T RUTHING Group work – 6 groups Pass out worksheets by group Compare the ground data to their map for the same area and present their findings to the class Using the satellite image, find other areas with the same spectral signature (i.e. same ground cover) Do we need to adjust our class definition of Ground Truthing? Look at your definitions.

SUMMARIZE Why is ground validation (ground truthing) so important for interpreting satellite imagery?

V ENN D IAGRAM F OLDABLE : E VALUATE GROUND TRUTHING & REMOTE S ENSING Ground TruthingBothRemote Sensing Tell how Ground Truthing is different from remote sensing Tell how they are alikeTell how Remote Sensing is different from ground truthing

Q UESTIONS & D IAGRAM How can remote sensing be used in the future What technology do scientists still need to invent?