Introduction to Remote Sensing Outline What is remote

Introduction to Remote Sensing

Outline • What is remote sensing? • The electromagnetic spectrum (EMS) • The four resolutions • Image Classification • Incorporation with GIS • Sample Research

What is remote sensing? • Remote sensing is the art and science of analyzing the Earth’s surface with remotely acquired data (most often from aircraft or satellites)

Electromagnetic Spectrum

Electromagnetic Spectrum • Remote sensing instruments can collect reflectance information in a wide range of the spectrum (visible, infrared, radar) • Different features reflect various amounts of energy from different parts of the spectrum • That is how we can distinguish and separate between features.

Spectral Reflectance of common features

The Four Resolutions Spectral Resolution • Refers to the section(s) of the EMS in which reflectance information is acquired • For example, the Landsat ETM+ sensor collects: -blue -mid infrared -green -mid infrared -thermal infrared -near infrared -panchromatic

The Four Resolutions Spatial Resolution • Refers to the size of a single pixel in an image (i. e. , the area for which individual reflectance values are recorded Landsat ETM+ - 30 m IKONOS Panchromatic– 1 m

The Four Resolutions

The Four Resolutions Radiometric Resolution • Refers to the range of reflectance values recorded • For example, 8 -bit data displays values ranging 0 -255 (28=256) Temporal Resolution • Refers to how often an image of the same area is collected, as determined by the sensor’s orbit and spatial resolution

Classification • The process of converting raw imagery to thematic information • Each pixel in the image gets placed into a certain class based on its reflectance compared to other pixels

Raw Image

Classified Image

Change Detection • Using images of the same area at different times to analyze what has happened between the two dates Landsat-1985 Landsat-2000

Change Detection

GIScience • Geographical Information Sciences (i. e. , the art and science of spatial analysis) • Data collected from a variety of sources can provide input for a GIS database because (provided) they are rectified to a common spatial reference (coordinate system, datum plane, projection) (e. g. , WGS 1984, UTM, Zone 30) • This includes remotely-sensed data

Image Backdrops • While classified imagery can be used as a layer in the GIS, raw imagery is often used as a backdrop for displaying point, line and polygon information

Questions?