本文回顧過去澎湖島嶼面積和海岸線測繪成果，並且分析測繪數據，來說明自然地理學與海岸地形學在海岸測繪工作中的重要性。透過海岸碎形分析，本文指出當前有關澎湖海崖後退與濱台發育的論述，仍有重要未知成份。僅利用濱台寬度與盛行波候，來討論海崖與濱台發育，這一種討論並不完整。現有資料無法決定澎湖濱台加寬速率與海崖後退速率，利用歷史記錄推論或者田野觀測崖面後退速率仍屬必要。這些地理知識和田野觀測不但對於驗證或否證崖面後退模式具有學術價值，對於澎湖河海工程和敷地設計，也具有應用價值。
In this study, the cartographical and geodetic surveys on defining the area and coastlines of Peng-Hu Islands are reviewed, and the significance of physical geography and coastal geomorphology in those surveys are addressed. Through the fractal analysis of coastlines of Peng-Hu Islands, it is suggested that there are still some unknown factors in the discourse of cliff retreat and shore platform development in Peng-Hu. The discourse of cliff retreat and shore platform can not be built completely based on the information of platform morphology and the wave climate only. While the available field survey data can not define the cliff retreat rate and the widen speed of the shore platform in this area, it is necessary to explore the geographical reasoning based on historical documents and/or to conduct the field monitoring on the cliff retreat rate. The geographical knowledge and process monitoring can be valuable for testifying Fisher-Lehmman Model, and for coastal engineering and site planning in Peng-Hu Islands.
