# Presentation: 248977

## Geography 372Introduction to Remote Sensing

- Geography 372Introduction to Remote Sensing

- University of Maryland
- Compton Tucker & Megan Weiner

## Remote Sensing Creed

**I want to understand the world**
**I must use the electromagnetic spectrum (few other options)**
**I will not be limited by a sensory system (the human eye) optimized for viewing things in the light from a 6000 K star 93M miles away, whose electromagnetic irradiance also has to pass through Earth’s N****2****-O****2**** planetary atmosphere**

## All alone in our neighborhood of space

**Apollo 12’s Classic Earth Rise from Moon**

## Slide 4

## Slide 5

## Remote Sensing Systems

- How do we discuss and catagorize remote sensing?
- “the resolutions”
**Spatial**** **Resolution -- what size we can resolve
**Spectral** Resolution -- what wavelengths do we use
**Radiometric** Resolution -- degree of detail observed
**Temporal** Resolution --  how often do we observe

## True & False Color Ikonos Satellite Data Beltsville Agricultural Research Center

**True & False Color Ikonos Satellite Data ****Beltsville Agricultural Research Center**

**In visible light these trees look the same**

**Near-infrared separates conifers (darker) from deciduous trees**

**400              500              600              700nm**

## Spatial resolution

**Spatial resolution**

**Each square in the image is one digital number for each spectral band. The dimensions of the square determines spatial resolution. **

## Better spatial resolution 

**Mars “Face” Viking 1976 resolution = ~200 m**

**Mars Orbiter 2000 resolution = ~10 m**

## Multistage Remote Sensing

**Multistage Remote Sensing**

## Ground-based remote sensing

**Ground-based remote sensing**

## Air Photo:color film, airplane,   1-2 m detailTimothyLake, OR

**Air Photo:****color film, airplane,   1-2 m detail****Timothy****Lake, OR**

## Landsat 30 m

**Landsat 30 m**

- Columbia River

- Mt. St. Helens Mt. Adams

## AVHRR 1 km

**AVHRR 1 km**

**Columbia River**

- Olympic Pen.

- Yellowstone N.P.

- Mt. St. Helens

## Satellite Remote Sensing of Earth

**SeaWiFS Land-Ocean Chlorophyll September 1997 to present ...**

## Remote sensing uses the radiant energy that is reflected and emitted from Earth at various “wavelengths” of the electromagnetic spectrum
Our eyes are only sensitive to the “visible light” portion of the EM spectrum
Why do we use nonvisible wavelengths?

**Our eyes are only sensitive to the “visible light” portion of the EM spectrum**
**Why do we use nonvisible wavelengths?**

**The Electromagnetic Spectrum**

## our star

- Our Sun emits more light in the visible than any other part of the spectrum.

## Amount of solar energy hitting Earth’s outer atmosphere is ~1370 watts/m2

- Amount of solar energy hitting Earth’s outer atmosphere is ~1370 watts/m2

## Rayleigh Scattering:why the sky is blue

**Rayleigh Scattering:****why the sky is blue**

## Remote Sensing Systems:the Human Eye

**Spectral** Resolution:  0.4-0.7 μm
**Spatial** Resolution:  ~ 1-3 cm @ 20 m
**Radiometric** Resolution: ~16-32 shades 				B/W or ~100 colors

## Invertebrate remote sensing

**Insects have remote sensing capabilities quite different from vertebrates and the octopus**

## Key Milestones in Remote Sensingof the Environment

**1826 – Joseph Niepce takes first photograph**
**1858 – Gaspard Tournachon takes first aerial photograph from a balloon**
**1913 – First aerial photograph collected from an airplane**
**1935 – Radar invented**
**1942 – Kodak patents color infrared film**
**1950s – First airborne thermal scanner**
**1957 – First high resolution synthetic aperture radar**
**1962 – Corona satellite series (camera systems) initiated by the Intelligence community**
**1962 – First airborne multispectral scanner**
**1972 – ERTS-1 Launched – First Landsat satellite**

**Notes:**
A good way to understand the science/technology of remote sensing is to briefly review its history

In reality, the science of remote sensing dates from the 1960s with the development of electro-optical remote sensing systems

The entire science of remote sensing was revolutionized in the early 1970s with the launch of the Earth Resources Technology Satellite-1, which was later renamed into Landsat

ERTS-1 provided the first synoptic view of the entire earth for civilian satellites

## Early photograph by J. Niepce circa1830 

**Early photograph by**** ****J. Niepce**** circa1830**** **

**Notes:**
Remote sensing has its foundation in photography.

Joseph Niepce created the first photograph in France in 1826

This photograph took 8 hours to expose

The original concepts of Diecpe were improved upon by Louis Daguerre, who created the first photographic plate, e.g., a film that could be exposed and processed.

Then, William Talbot invented the process whereby film negatives could be used to create positive prints.

## Nadir in his balloon

**Nadir in his balloon**

**Notes:**
The next development in remote sensing occurred in 1858

This is when Gaspard Tournachon (who liked to call himself Nadar) took a picture from a balloon, creating the first aerial photograph

## Nadir photograph of Paris

**Nadir photograph of Paris**

**Notes:**
Here is an aerial photograph that Tournachon took along the riverfront in St. Louis

Demonstrated that photography could be used to create an accurate spatial representation of the earth’s surface

Up until this time, map makers were limited in their ability to make renditions of the earth’s surface based upon tedious and time consuming ground-based surveys

## Balloon Photo of Boston 1836

**Balloon Photo of Boston 1836**

## Thaddeus Lowe’s Civil War Balloons U.S.Army of the Potomac 1861-1865

- Massachusetts’ man, Professor and visionary, Lowe Observatory/Calif.
- Platform:       **Balloon**
- Sensor:          **Telescope**
- Data System: **Telegraph**

## Thaddeus Lowe, circa 1861-1865 remote sensing for military purposes. Then, as now, newest developments are always in the military sphere

## Remote sensing early in the airplane era

**Remote sensing early in the airplane era**

**Notes:**
When airplanes were invented in the early 1900s, this lead to the use of this platform for collection of aerial photographs

Aerial photography was extensively used in WWI

Top is a hand held operation

Bottom is a mounted camera system

## U-2 Spy Plane 1954-1960Flew at 70,000’ over USSR air defenses

## SR-71 Blackbird super-sonic spy plane

**Notes:**
This was followed by the SR 71

## CIA’s Corona Program1960-1972 >100 missions

- Followed after U-2s...
- Platform:       **Spacecraft**
- Sensor:              **Camera**
- Data System: **Film Drop**
- Started:**       August 1960**
- Coverage:       **7.6 Bil mi****2**

- Spatial Resolution:  early missions @ 13 m, later missions @ 2 m
- Spectral Resolution: visible and visible-near infrared (both film)
- Radiometric Resolution: equivalent 24 to 26 (4 to 6 bits)

## CIA’s Corona ProgramWashington Monument 1967

## Ikonos 1 m panchromatic imagery

**Ikonos 1 m panchromatic imagery**

**2000**

**Notes:**
We are now to the point where we can collect high resolution photography from spaceborne digital camera systems on a commercial

## MODIS Land Reflectance and Sea Surface Temperature

**MODIS Land Reflectance and Sea Surface Temperature**