Image alignment of historical and current Cebu maps to determine river path changes and flooding pattern

Two historical maps of Cebu City dated 1833 and 1873 were digitized and piecewise linearly transformed to align street maps with current Google Maps of the city. The calculated RMS errors of the transformed maps are established to be comparable with other studies. Disappearance of water basins and river path changes were observed in the current map. Overlaying a flood hazard map on the transformed historical maps reveals a correlation between sites of reclamation and river path changes with current flood prone areas. Old maps can inform land use planners about ancient water ways that can become flooding hazards if improperly managed.