Aerial Photography and Remote Sensing

These materials were developed by Shannon Crum, Department of Geography, University of Texas at Austin, 1995.  These materials may be used for study, research, and education in not-for-profit applications.  If you link to or cite these materials, please credit the author, Shannon Crum, The Geographer's Craft Project, Department of Geography, The University of Colorado at Boulder.  These materials may not be copied to or issued from another Web server without the author's express permission.  Copyright © 2000 All commercial rights are reserved.  If you have comments or suggestions, please contact the author or Kenneth E. Foote at k.foote@colorado.edu.

This page is available in a framed version. For convenience, a Full Table of Contents is provided.



Introduction

Foundations of Remote Sensing


Aerial Photography


Digital Image Processing

Why Process Remotely Sensed Data Digitally?

Humans are adept at visually interpreting data. We can distinguish millions of colors, several shades of gray, and have a demonstrated ability to identify water, vegetation, and urban forms on several types of imagery. Why try to expand on this?
 

The processes of manual image interpretation and digital image interpretation are similar in many ways. The goals of analysis are often the same, though the routes may vary.

Sources of Digital Data

Image Enhancement

Data Classification


Satellite Imaging

Introduction

Landsat
 

LANDSAT refers to a series of satellites put into orbit around the earth to collect environmental data about the earth's surface. The LANDSAT program was initiated by the U.S. Department of Interior and NASA under the name ERTS, an acronym which stands for Earth Resources Technology Satellites. ERTS-1 was launched on July 23, 1972, and was the first unmanned satellite designed solely to acquire earth resources data on a systematic, repetitive, multispectral basis. Just before the launch of the second ERTS satellite, NASA announced it was changing the program designation to LANDSAT, and that the data acquired through the LANDSAT program would be complemented by the planned SEASAT oceanographic observation satellite program. ERTS-1 was retroactively named LANDSAT-1, and all subsequent satellites in the program have carried the LANDSAT designation. Over time, the sensors carried by the LANDSAT satellites have varied as technologies improved and certain types of data proved more useful than others. The table which follows outlines the sensors onboard each satellite, their launch dates, and the dates they were decommissioned.

Table 1
 

The various Landsats have had Multispectral Scanners (MSS), Return Beam Vidicon (RBV) scanners, and Thematic Mapper (TM) scanners. Each type has its own spectral range and spatial resolution.

Interpreting Landsat Data

The images discussed in this section are the property of the University of California, Santa Barbara. Click here to get to the Center for Ecological Health Research Home Page, then click on the image indicated below, then back up to this page with the image still visible to read the discussion that pertains to the image. Detailed explanations of the images will be added soon.
 


SPOT

NOAA AVHRR

NOAA Geostationary and Polar Orbiting Satellites

NOAA GOES mission overview and history. The GOES graphic was prepared by the NASA Goddard Space Flight Center, which provides additional information about the GOES project.

The first visible GOES-8 image. Look carefully and you can make out Baja California on the lower left and Lake Michigan on the upper right.

Applications of Satellite Imagery

Integration of Satellite Imagery into GIS


Further Reading

Bauer, M.E., T.E. Burk, A.R. Ek, P.R. Coppin, S.D. Lime, T.A. Walsh, D.K. Walters, W. Befort, and D.F. Heinzen. Satellite Inventory of Minnesota Forest Resources. Photogrammetric Engineering and Remote Sensing, in press.


MSS, Thermal, and Hyperspectral Scanning

Thermal Radiation Principles

Thermal infrared radiation refers to electromagnetic waves with a wavelength of between 3.5 and 20 micrometers. Most remote sensing applications make use of the 8 to 13 micrometer range. The main difference between THERMAL infrared and the infrared discussed above is that thermal infrared is emitted energy, whereas the near infrared (photographic infrared) is reflected energy.

Multispectral Scanning

Interpreting Thermal Scanning Imagery

Limitations of Thermal Infrared Imaging

There are some limitations of thermal imagery you should be aware of if you plan to use it in your GIS:

FLIR systems

Imaging Spectrometry


Radar (Microwave) Scanning

Introduction:

SLAR

LIDAR

ERS Program

Radar Images

The following radar images come from sites all over the world. The files at NASA's Jet Propulsion Laboratory have explanations accompanying the images.

Spaceborne Synthetic Aperture Radar, Oetxal, Austria. This file was created by NASA's Jet Propulsion Laboratory in Pasadena, CA.


Remote Sensing and GIS

To sum up, remotely sensed images have a number of features which make them ideal GIS data sources.

Last updated 2000.2.6. LNC.