Remotely-sensed data

aerial imagery

aerial imagery

Gaspar Felix Tournachon, more commonly known as “Nadar,” is credited with taking the first successful aerial photograph in 1858 from a hot air balloon tethered 262 feet over Petit-Bicêtre (now Petit-Clamart), just outside Paris; his original photos have been lost.

aerial imagery

“Boston, as the Eagle and the Wild Goose See It”

October 13, 1860

by

James Wallace Black is the earliest surviving aerial photograph.

Credit: James Wallace Black, The Metropolitan Museum of Art.

aerial imagery

Photograph of San Francisco in ruins from Lawrence Captive Airship, 2000 feet above San Francisco Bay overlooking water front. Sunset over Golden Gate circa 1906

George Lawrence—Prints & Photographs Divison/Library of Congress

aerial imagery

satellite imagery

First image of Earth from outer space, taken by the V-2 No. 13 suborbital spaceflight.

October 24, 1946

The first crude image taken by a satellite, Explorer 6, shows a sunlit area of the Central Pacific Ocean and its cloud cover. The photo was taken when the satellite was about 17,000 mi (27,000 km) above the surface of the earth on August 14, 1959. At the time, the satellite was crossing Mexico.

Corona Program

Mission 13

10 August 1960

In one mission, Corona imaged 1.5 million square miles of Soviet territory. It revealed 64 new Soviet airfields and 26 missile sites.

Corona satellites would go on to fly more than 130 missions, taking more than 800,000 photographs of the entire Soviet Union and much of the world.

Landsat

the value of remote sensing data

broad coverage

spectral range

geometric accuracy

Imaging Systems

passive systems

image scanners

active systems

geophysical prospecting

imagery properties

Radiometric Resolution

Spectral Resolution

spectral curves

Cadence (Revisit Rates)

• Landsat - 16 days
• Sentinel 2 - 10 days at the equator, 2-3 at mid-latitudes
• Planetscope Doves - Daily
• MAXAR/SkySat/Pelican - varies, tasked

image enhancement

stretching & clipping

rendering methods

pan-sharpening

imagery interpretation

Band Combinations

visible

infrared

8-bit color

Band Combinations

Band Combinations

Bands 3,2,1

Bands 4,3,2

Bands 7,4,2

Band Math (Indices)

Normalized Difference Vegetation Index (NDVI) = (NIR - R) / (NIR + R)

Landcover Classification

Landcover Classification

Commonly used  algorithms for supervised classification in remote sensing, include:

random forest (RF)

artificial neural networks (ANN)

 support vector machines (SVM)

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