An Aerial Photography - Aided Seaweed Bed Survey Techniques
Overview of Seaweed Bed Distribution Survey Process
Figure 1 is a general flowchart of the process of performing a seaweed bed distribution survey with the aid of vertical color aerial photographs.
Figure 1 General Flow chart of seaweed bed distribution survey process
Although some amount of field surveying is indispensable in order to determine the types and densities of seaweed beds, no matter which photo analytic technique is applied, rough photo reading can lessen the workload to a level much lower than is necessary with field surveys alone.
Photo analytic techniques and their features
Reading photos by eye
The technique of reading photographs through a mirror-type stereoscopic or directly by eye is applied to the classification of seaweed beds according to photo reading keys.
There are three types of photo reading keys; "tone", "texture," and "Pattern" seaweed bed in the light of established correspondences between photographs and field survey results, as in the keys listed in Table 1:
Table 1 Photo reading keys (Example)
This technique is the most widely used method now a days because it required no special apparatus or equipment. Yet, it presupposes that the photo reader has expertise and can avoid making arbitrary subjective judgement.
