Normalised Difference Vegetation Index (NDVI) was derived
from Landsat-5 TM scenes (183 172.8 km) provided by the European
Space Agency (ESA) [23] in the Universal Transverse Mercator
(UTM) coordinate system with a 30 m pixel spacing. Scenes
were selected for dates during the late growing season (September
2011) for comparison to the harvest data. Landsat-5 TM Level 1
System Corrected data had undergone pre-flight and in-flight
radiometric calibration [24] and was geometrically accurate
within 1 sigma [23,25]. The nearest neighbour (NN) resampling
algorithm preserves the maximum original radiance values, and
makes it free from distortions from the sensor, satellite or Earth
[26,27]. The satellite imagery was pre-processed in ERDAS Imagine
10 to remove undesirable image characteristics, correct for geometric
distortions and calculate NDVI.