Department of Geomatics Remote Sensing Applications

1
Department of Geomatics Remote Sensing
Applications

• VEGETATION

2
Department of Geomatics Remote Sensing
Vegetation

• Green vegetation has a distinctive reflectance
  curve
• Absorption in blue
• Reflection in green
• Absorption in red
• Strong reflection in NIR

3
Department of Geomatics Remote Sensing
Vegetation

• Green vegetation has a distinctive reflectance
  curve

4
Department of Geomatics Remote Sensing
Applications Vegetation

• This reflectance curve is due to
• Visable
• Plant pigments (particularly chlorophyll)
• Concentrated in the palisade cells
• NIR
• Cell moisture
• Result of the structure of the spongy mesophyll

5
Department of Geomatics Remote Sensing
Applications

• VEGETATION

6
Department of Geomatics Remote Sensing
Applications Vegetation

• Vegetation cover can be mapped by
• A simple vegetation ratio
• NIR/R
• Contrast with FeO or Clay ratio
• Works best for green, broad leafed plants
• Doesnt work as well for forest
• Doesnt work at all well for conifers

7
Department of Geomatics Remote Sensing
Applications

• VEGETATION

8
Department of Geomatics Remote Sensing
Applications

• VEGETATION

9
Department of Geomatics Remote Sensing
Applications Vegetation

• Mapping plant species
• Depends on leaf/ canopy structure
• Most change in the NIR
• Smaller changes in leaf pigments
• Easy to tell difference between major groups (eg.
  forest/grass, pine/eucalypt)
• Difficult to map differences within major groups

10
Department of Geomatics Remote Sensing
Applications

• VEGETATION

11
Department of Geomatics Remote Sensing
Applications

• VEGETATION

12
Department of Geomatics Remote Sensing
Applications

• VEGETATION

13
Department of Geomatics Remote Sensing
Applications Vegetation

• NIR reflectance
• Will change with stress
• Disease
• Water stress
• Old age
• Changes before Visible

14
Department of Geomatics Remote Sensing
Applications

• VEGETATION

15
Department of Geomatics Remote Sensing
Applications Vegetation

• NIR reflectance
• Shows where a problem is occuring
• Does not identify the problem
• Will detect the problem prior to visible
  inspection
• Will monitor recovery

16
Department of Geomatics Remote Sensing
Applications Vegetation
17
Department of Geomatics Remote Sensing
Applications Vegetation
18
Department of Geomatics Remote Sensing
Applications Vegetation

• Vegetation health is best mapped by
• Normalised differential vegetation index - NDVI
• NIR-R/NIRR
• Images should be normalised first
• Can also use the Greeness Index
• (sensor specific)