Ariake Bay in Japan is known for the large difference between its highest and lowest tides, plentiful supply of oysters and Mutugoro fish. Recently in this area, the populations of small oysters (i.e. C. Gigas and C. Riunlaris species) have been increasing because these small oysters have no commercial value and are not cought by fishermen. The thick layer of small oyster that was accumulated on the floor of the sea prevents fishermen from carrying out their work. So, fishermen want to know the distribution and value of these small oyster in preparation for removing this layer by dreging. To know the horizontal distribution of these small oysters, colour aerial photo interpretation was very useful and to know the vertical distribution of these small oysters, ultra sonic exploration of several frequencies was very useful. The frequency of 2.5-9.0 KHz was most useful to detect the thickness of the layer of these small oyster.
The use of photogrammetry is limited in making a topographic map, but its useful application to the other scientific field which has been studying. The measurement using a non-metric camera had not been practical, because of the difficulty of correcting systematic errors of the camera. Recently the application of a non-metric camera to photogrammetric mensurations has been reported. Highly accurate measurement with a non-metric camera can be expected by correcting the systematic errors of the camera. This report describes the result on the measurement obtained with the application of the Cameron effect due to false parallax. In our official trial in soil engineering field, we have studied on the application of the Cameron effect with respect to the settlement phenomenon in local media.