GIS 255 Final

• 1. Maximize sensitivitiy to plant biophysical parameters
• 2. Normalize or model external effects such as sun angle, viewing angle, and the atmosphere
• 3. Normalize internal effects such as canopy background variations, soil variations, and differences in senesced vegetation.
• 4. Be coupled to a specific measureable biophysical parameter

ETM Band 5 / (ETM Band 1 + ETM Band 2 + ETM Band 3), because Band 5 has low reflectivity for snow but high reflectivity for clouds.

Band 1.

Different atmospheric constituents (gases, aerosols, and clouds) can causes unwanted path radiance at the sensor which can show up as change when no change has occurred. Compensation may be as simple as converting to reflectance before change detection or as complicated as running atmospheric correction routines to eliminate/reduce the effects of the atmosphere.

L1T because it has the highest geodetic accuracy, utilizing GCPs and a DEM. L1Gt only uses a DEM and L1R has no geometric correction applied.

Histogram matching increases the contrast of the images, allowing for a more effective difference image.

Radiation that was reflected by nearby terrain (p lambda) covered by snow, water, concrete, vegetation, etc. into the IFOV.

Path 2 and Path 4; generally to be avoided.

Paths 1, 3, and 5; generally valuable.

Radiance that was reflected by nearby terrain into the atmosphere before being reflected back into the nearby study area.

Because images from 2 different platforms are calibrated and compared againts each other and those images are never captured with exactly identical configurations and the processing of the images must compensate for the differences in illumination and observation angles.

Because data acquisitions were only 10 to 30 minutes apart during the tandem configuration period, it is assumed that the surface and atmospheric conditions did not change significantly between the two image acquisitions. For Landsat sensor image data pairs acquired during the tandem configuration period, the expectation is that such adjustments are not necessary.

• It provides reformatted raw data with no geometric or radiometric correction applied. Reformatting includes shifting pixels by integer amounts to account for
• -The alternating forward-reverse scanning pattern of the sensor;
• -The odd-even detector arrangement within each band, and
• -The detector offsets inherent to the focal plane array engineering design.

Energy from the Sun that has undergone some scattering and perhaps some absorption or reemission before illuminating the study area.

It provides systematic radiometric accuracy, geometric accuracy by incorporating ground control points, while also employing a digital elevation model (DEM) for topographic accuracy. Geodetic accuracy of the product depends on the accuracy of the ground-control points and the resolution of the DEM used.

Red.

Lt and Lp

When the diameter of the air (or whatever) molecules is many times smaller than the wavelength of the incident electromagnetic radiation.

When the molecules are essentially spherical and w/diameters approximately equal to the length of the incoming wavelengths.

Convert to reflectance.

It provides systematic geometric and radiometric accuracy, which is derived from data collected by the sensor and spacecraft. The scene will be rotated, aligned, and georeferenced to a user-specified map projection. Geometric accuracy of the systematically-corrected product should be within 250m for low-relief areas at sea level.

For relatively clear Landsat scenes, a reduction in between-scene variability can be achievedthrough a normalization for solar irradiance by converting spectral radiance, as calculatedabove, to planetary reflectance or albedo.

Spectral diffuse sky irradiance (Ed) that never reaches the target b/c of scattering in the atmosphere.

It provides systematic radiometric and geometric accuracy, while using a DEM for topographic accuracy. The latter depends on the resolution of the DEM used.

Maximum likelihood, minimum distance/nearest mean, Mahalanobis.

K-means, ISODATA, parallelepiped.

Theta.

• 1. Spectral characterization
• 2. Radiometric calibration
• 3. Spherical integrating source

• 1. Internal calibrator.
• 2. Full-aperture solar C.
• 3. Partial-aperture solar C.

Radiometrically corrected.

Radiometrically and geometrically corrected.

Terrain-corrected.

• Tone
• Texture
• Pattern
• Shape
• Size
• Association

National Image Interpretability Ratings

10 (from 0 to 9)

(reflectance NIR - reflectance red)/(reflectance NIR + reflectance red)

One that assumes a particular class statistical distribution (e.g., normal) for classification.

One that makes no assumptions about probability distributions.

Unsupervised (requiring no input from the user to cluster pixels in a dataset, but based on statistics only).

Supervised.

Level 1.

Level 3.

Level 5.

Yes.

Yes.

Level 4.

Level 7.

Between 0.43 and 0.66 micrometers.

Between 0.45 and 0.65 micrometers.

The x-axis is red reflectance, the y-axis is near-infrared reflectance; the "tassel" is high canopy closure or biomass, the left corner is wet bare soil, the right corner (somewhat above the former) is dry bare soil.

Reflectance NIR/Reflectance red

• Lp (atmospheric path reflectance, never touches the surface)
• Ls (free-surface layer reflectance, bounces off the surface)
• Lv (subsurface volumetric reflectance, reflected off some point below the surface)
• Lb (bottom reflectance)

Below 400 nm.

Ultraviolet (<400 nm) and yellow through near-infrared (>580 nm) portions of the spectrum.

Near-infrared and middle-infrared (740-2500 nm)

longer wavelengths.

Below 1.5

Approximately same as snow below 1.5, slightly less but still almost the same above.

• 1. Phenological change
• 2. Sun angle effects
• 3. Atmospheric effects
• 3. Geometric effects

Can be dealt with by radiometric calibration, anniversary-date acquisition, and highly accurate registration.