Welcome to Introduction to GIS Software: QGIS, Class 11
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Georeferencing
find landmarks easily discerned in both your image and the reference map
use as few points as you can, to start
remote sensing
Landsat
the longest continuous satellite imagery collection program
Landsat is "earth observing", as opposed to people observing (spying)
1972: first Landsat satellite launched
1985: Landsat is privatized, run by Hughes and RCA
2001: Landsat fully returned to public hands
2007: all Landsat imagery becomes free
2013: Landsat 8 launched
Landsat imagery is used for:
- irrigated water monitoring
- irrigated water monitoring
- land cover mapping
- irrigated water monitoring
- land cover mapping
- land use change studies
- irrigated water monitoring
- land cover mapping
- land use change studies
- invasive species detection and monitoring
- irrigated water monitoring
- land cover mapping
- land use change studies
- invasive species detection and monitoring
- coastal wetlands monitoring
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resolution: how much area on the ground is represented by one pixel
if a satellite has 30m resolution, each pixel represents a 30m x 30m square
a smaller number for resolution is better
revisit rate or temporal resolution
how frequently does the satellite take a picture of a given location?
bands
satellites produce a number of images at different wavelengths
bands 2, 3, and 4 (blue, green, and red)
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band 6 and 7 (shortwave infrared)
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you will combine bands to suit your needs
LiDAR
light detection and ranging
LiDAR actively uses lasers and sees how long it takes for a reflection to arrive
like SONAR (sound) and RADAR (radio waves)