A 2m by 2m canopy height model (CHM) grid developed from the 2011 aerial LiDAR survey of Christmas Island. As with the 2011 DEM, the CHM was provided to Geoscience Australia in 1km by 1km ESRI grid tiles, which were then joined together using ESRI ArcMap.
Each grid cell (2m x 2m) contains the maximum vegetation height in metres. Canopy height was generated by subtracting the ground height from the first laser return classified as vegetation. As a guide, the data is vertically accurate to 15cm and horizontally accurate to 30cm. For a detailed description of the survey accuracy see the AAM Survey Report. The CHM grid file was provided in GDA94 MGA zone 48 and has been left in this projection.
The CHM data can be used to find the average vegetation canopy height for defined areas. LiDAR vegetation heights, along with vegetation density values have been used in other organisations to create vegetation maps, estimate carbon content, characterise species habitats and assist in decision making.