Abstract
It is common to realize in literatures that shoreline position extracted from unknown capture time aerial photograph or satellite image (hereafter referring both kinds as image) has not been corrected to tidal effect. One of reasons is due to missing capture time of satellite image which was collected from open sources or captured a long time ago. However, the correction of tide for shoreline position extracted from image is highly required for studies in the field of coastal morphology changes. Especially, in the developing country, where field data is very limited, shoreline data extracted from satellite image plays more important role. There approaches, which can estimate the capture time of image based on the solar height and the length of shadow of vertical object on the horizontal surface on the earth, are introduced in this study. The capture time estimated from solar height has much smaller error compared to that from length of shadow. This error is acceptable for the tidal correction purpose. The temporal variation of shoreline positions of cases without and with tidal correction has been shown.
