6      Advantages of LiDAR technology

The other methods of topographic data collection are land surveying, GPS, inteferrometry, and photogrammetry.   LiDAR technology has some advantages in comparison to these methods, which are being listed below:


o    Higher accuracy

n  Vertical accuracy 5-15 cm (1s)

n  Horizontal accuracy 30-50 cm


o  Fast acquisition and processing

n  Acquisition of 1000 km2 in 12 hours.

n  DEM generation of 1000 km2 in 24 hours.


o  Minimum human dependence

n  As most of the processes are automatic unlike photogrammetry, GPS or land surveying.


o  Weather/Light independence

n  Data collection independent of sun inclination and at night and slightly bad weather. 


o  Canopy penetration

n  LiDAR pulses can reach  beneath the canopy thus generating measurements of points there unlike photogrammetry.   


o  Higher data density

n  Up to 167,000 pulses per second. More than 24 points per m2 can be measured.

n  Multiple returns to collect data in 3D.


o  GCP independence

n  Only a few GCPs are needed to keep reference receiver for the purpose of DGPS.  There is not need of GCPs otherwise. 

n  This makes LiDAR ideal for mapping inaccessible and featureless areas.


o  Additional data

n  LiDAR also observes the amplitude of back scatter energy thus recording a reflectance value for each data point.  This data, though poor spectrally, can be used for classification, as at the wavelength used some features may be discriminated accurately. 


o  Cost

n  Is has been found by comparative studies that  LiDAR data is cheaper in many applications.  This is particularly considering the speed, accuracy and density of data.