Remote Sensing
- Collection of information without being in contact.
EM Spectrum in RS
- Near UV: 0.3 - 0.4 micrometer
- Visible: 0.4 - 0.7 micrometer
- IR: 0.7 - 14 micrometer
- Microwave: 0.3 to 300 cm
Visible & IR mostly used.
How EMR used in RS
- Passive: Energy source from somewhere else (e.g., Sun)
- Active: Self generated beamed energy for reflection (e.g., when sunlight not sufficient or at night)
- Scattering
- Transmission
- Reflection:
- Reflectance = \frac{Rs}{I} [impo]
NDVI
- For LandSat 8, band 4, 5 [check]
- (5 - 4) / (5 + 4)
Procedure
- Import relevant TIF files
- Search and open
Raster Calculator
- Expression:
Float("LO08_L1TP_137044_20201109_20201120_02_T1_B5.TIF"-"LO08_L1TP_137044_20201109_20201120_02_T1_B4.TIF")/Float("LO08_L1TP_137044_20201109_20201120_02_T1_B5.TIF"+"LO08_L1TP_137044_20201109_20201120_02_T1_B4.TIF")
- Set color ramp or reclassify
NDBI (Built-up Index)
- Point of confusion: "chor" may give similar reflectance of building