Exam II Flashcards
What are biophysical variables?
Characteristics a satellite image can sense
List direct biophysical variables?
- x, y
- elevation
- color
- biomass
- moisture
- heat
List hybrid biophysical variables?
- land cover/ use
- stress
- productivity
What is a Geotiff?
A TIFF file that has been geocoded
What has better resolution, TM or MSS?
Thematic mapper (TM) has better resolution (16 scan lines) than Multispectral Scanner (MSS) (6)
Landsat vs SPOT?
Landsat (whiskbroom scanner):
- MSS, TM
SPOT (pushbroom scanner):
- Pan, HRV
Radiometric correction, why?
- Large area
- Difference sum angles
- Extend results to other areas
- Compare to other data
What are detector errors?
Errors that affect the quality of a satellite data set
Types of detector errors?
- Line dropout - one detector fails (Fix: Avg. #s) (Results in failure from Landsat**)
- Destripping - detector drift
What is histogram subtraction?
Adjusting for atmospheric scatter via simple math
- subtract min DN from each band
What happens as a result of Raleigh scatter?
DNs increase
What is histogram regression?
Adjusting for atmospheric scatter via regression techniques
- No ref. in IR Regions
- Regress pixels in clear deep water and shadows
What is geometric correction?
Projecting image data onto a flat plane to conform to a map projection
Ways to tell if an image has been geometric corrected?
- Inquire
- Measuring tool
- Check MetaData
Geometric correction, step 1?
Locate GCP’s
- pixels found on map and image
- min # of GCP’s = ((t+1)(t+2)/2