Colour composites

Dr Nigel TroddCoventry University

Single band of data

grey levels correspond to digital numbers (DN)

Multispectral colour composite

3 gun monitor

1 band of data displayed thru’ 1 colour gun

Multiband selection

Landsat ETM+

spectral region role

1 Blue map shallow water bodies, identify forest type

2 Green discriminate vegetation & assess vigour, detect man-made objects

3 Red identify plant species & phenological status, detect man-made objects

4 Very Near IR Identify plant species, assess vigour & estimate biomass, delineate water bodies, estimate soil moisture

5 Short Wave IR delineate water bodies, estimate vegetation & soil moisture, differentiate snow from cloud cover

6 Thermal IR estimate soil moisture, analyse vegetation stress

7 Short Wave IR Identify rock type & mineralisation, estimate vegetation moisture

Panchromatic detect objects, locate boundaries

Mapping coastal waters

spectral region role

1 Blue map shallow water bodies, identify forest type

2 Green discriminate vegetation & assess vigour, detect man-made objects

3 Red identify plant species & phenological status, detect man-made objects

4 Very Near IR Identify plant species, assess vigour & estimate biomass, delineate water bodies, estimate soil moisture

5 Short Wave IR delineate water bodies, estimate vegetation & soil moisture, differentiate snow from cloud cover

6 Thermal IR estimate soil moisture, analyse vegetation stress

7 Short Wave IR Identify rock type & mineralisation, estimate vegetation moisture

Panchromatic detect objects, locate boundaries

Monitoring crops

spectral region role

1 Blue map shallow water bodies, identify forest type

2 Green discriminate vegetation & assess vigour, detect man-made objects

3 Red identify plant species & phenological status, detect man-made objects

4 Very Near IR Identify plant species, assess vigour & estimate biomass, delineate water bodies, estimate soil moisture

5 Short Wave IR delineate water bodies, estimate vegetation & soil moisture, differentiate snow from cloud cover

6 Thermal IR estimate soil moisture, analyse vegetation stress

7 Short Wave IR Identify rock type & mineralisation, estimate vegetation moisture

Panchromatic detect objects, locate boundaries

Mapping urban areas

spectral region role

1 Blue map shallow water bodies, identify forest type

2 Green discriminate vegetation & assess vigour, detect man-made objects

3 Red identify plant species & phenological status, detect man-made objects

4 Very Near IR Identify plant species, assess vigour & estimate biomass, delineate water bodies, estimate soil moisture

5 Short Wave IR delineate water bodies, estimate vegetation & soil moisture, differentiate snow from cloud cover

6 Thermal IR estimate soil moisture, analyse vegetation stress, thermal mapping

7 Short Wave IR Identify rock type & mineralisation, estimate vegetation moisture

Panchromatic detect objects, locate boundaries

Summary: 3 steps

1. Identify individual waveband(s)2. Combine (upto) 3 bands3. Allocate one band of data to one

colour gun