Title: Spectral library creation and analysis of urban built-up surfaces and materials using field spectrometry

Abstract

Hyperspectral remote sensing data by virtue of its capability to discern between different types of urban construction materials and surfaces is extremely useful in the study of various urban impervious surfaces and its effect on urban environment. There are a variety of urban built up materials and surfaces that can be distinguished only by using their comprehensive spectral characteristics. This paper presents a study that deals with creation of spectral libraries and statistical analysis of spectral signatures of urban built-up surfaces and materials. Field measurements have been carried out using Spectro-radiometer over the wavelength range of 350 to 2500 nm. Further, this study investigates the unique spectral characteristics and complexity of heterogeneous urban environments using mean spectral signatures of major built-up surfaces and materials. The study area belongs to the Udaipur, Rajasthan, India, which is an amalgamation of urban built-up and non built-up surfaces. Although the spectral libraries have been created for Roof/Building, Roads/ Pavements, Railway Track, Sports Infrastructure etc, spectral signatures of only Roof /Building surfaces are shown here in the Table – 1 below. The results of the analysis suggest that various built-up surfaces and materials can be identified by investigating different absorption features in different spectral regions of a particular urban built-up class. The analysis of pervious / non built-up surfaces can be further enhanced by adding some more parameters in spectral characterization of the material. Besides, significant wavelengths can be identified by analysing the absorption features present in the spectra of different materials and the same may be utilised for mapping and area estimation of a particular type of built up material and/or surface.