Using Remote Sensing to Identify Illegal Crop Plantation
Identification of Cannabis plantation
By Manuel Lukas
Vegetation Around the Study Area
Since cannabis plantation in the study area were grown under trees’ canopy, it is important to know the type of trees that exists around the site. From the GIS data obtained from Geoscience Australia (GA), it is known that the location of the site is classified as a native vegetation area. Therefore, a further research was done by using NSW Native Vegetation Map (http://maps.environment.nsw.gov.au/stateveg/default.htm) to find out the class of native vegetation the area is belong to.
Based on the map (updated in 2005), 10-50% of the land cover is the type of vegetation classified as Southern Tableland Dry Sclerophyll Forest. The types of trees exist in the Southern Tableland Dry Sclerophyll Forest are (DEC, 2005);
· Eucalyptus macrorhyncha (red stringybark),
· Eucalyptus rossii (scribbly gum),
· Eucalyptus dalrympleana subsp. dalrympleana (mountain gum),
· Eucalyptus cinerea (Argyle apple),
· Eucalyptus. dives (broad-leaved peppermint),
· Eucalyptus mannifera (brittle gum),
· Eucalyptus radiata subsp. radiata (narrow-leaved peppermint),
· Eucalyptus robertsonii subsp. robertsonii,
· Eucalyptus albens (white box),
· Eucalyptus goniocalyx (bundy), On drier and deeper soils
· Eucalyptus nortonii (large-flowered bundy).
To be certain that the study area is in the correct location on the map is very critical for the image analysis.
Since satellite imagery is displayed in reflectance value without a known geographic information, several comparison with other maps was carried out. This involves comparison the use of GIS data obtained from Geoscience Australia, which then overlap on top of the satellite imagery. With the known location of study area.
Another approach is by obtaining coordinate in an online map and plot it in the satellite digital image to observe the location on the digital image. Features such as river channel, lakes, and important infrastructure was observed.