Methodology for creating surface water database using GIS tools and remote sensing

Abstract

Although having a digital surface water database seems obvious in today’s digital era, earlier studies show persistent shortcomings, errors, and outdated spatial information on hydrographic networks. A response to this need is the integration of geographical information systems (GIS) and remote sensing tools, using orthophotomosaics from photogrammetric flights in various spectral ranges and converting them into vector data on water extent. Using the example of the Polish administration, this article synthesises the structure of the existing surface water database and proposes a coherent, optimised, and scalable methodology for its development. The workflow covers both attribute design and an automated process for acquiring geometric information with GIS and remote sensing techniques. The methodology includes: (1) analysing attribute requirements through a survey; (2) acquiring and processing photogrammetric imagery from two altitudinal levels (aerial and unmanned aerial vehicle – UAV) and elevation data (digital terrain model/digital elevation model (DTM/DEM) derived from LAS point clouds); (3) automatic water detection using the normalized difference water index (NDWI) and elevation model classification; (4) assessing the accuracy of generated stream centrelines by comparing them with global positioning system (GPS) field measurements and performing statistical correlation analysis; and (5) developing a database structure supported by empirical evidence. Such automation enables rapid production of hydrographic information and ensures uniform data acquisition at a supra-regional scale. Consequently, the proposed methodology provides a foundation for a unified, automated, and scalable surface water inventory suitable for national and international applications.