Abstract
The paper presents a sequential use of the AWK and GNU Octave programming languages integrated with Generic Mapping Tools (GMT) for geospatial data analysis. The geographic scope of the research is focused on the Kuril-Kamchatka Trench, north Pacific Ocean. Practical research aim is to analyse and compare bathymetry in the southern and northern part of the trench using digitized cross-section profiles. The initial mapping and geospatial analysis was performed in GMT scripting toolset. The GMT was used for cartographic mapping based on the raster ETOPO1 grid and automatic digitizing of the profiles crossing the trench perpendicularly. Besides visualized map, the processed geodata were received in a numerical form as a complex multi-field table for each segment. These tables were generated by the GMT in its native format and could not be directly processed by the MATLAB/Octave. Therefore, the tables were exported to AWK, a data-driven programming language and a powerful tool for data extraction. The table was then restructured, sorted and reshaped by the AWK script. Because the total amount of profiles overstepped 100 (62 and 52 for the northern and southern trench segments), only selected profiles were visualized. For this purpose, at the next step, the modified tables were converted to GNU Octave language for visualizing and plotting selected profiles. Finally, the geomorphology was analysed and two segments compared. The results show that the southern part has deeper bathymetric values, vary in geomorphic structure and has steeper gradient slopes comparing to the north, which is caused by the seismicity, volcanism, geologic and tectonic settings. Three full scripts of GMT, AWK and GNU Octave programming languages are presented for replicability in the Appendix. Keywords: AWK, Octave, GMT, programming language, data analysis, geospatial analysis, trench DOI 10.35180/gse-2019-0020
Highlights
The conceptual idea of this research consists in a chain of data processes by Generic Mapping Tools (GMT) cartographic scripting toolset and programming languages AWK and Octave
It can be explained by the fact that the northern part of the trench affected by numerous earthquakes located on the Kamchatka Peninsula is influenced by a large amount of the accumulated sediments
The profiles in the northern part of the trench show deeper values and less steep slopes comparing to the southern segment, which refer to the erosional moats and drift of the submarine sediments
Summary
The conceptual idea of this research consists in a chain of data processes by GMT cartographic scripting toolset and programming languages AWK and Octave. The experimental novelty of this research is integration of the three tools, – GMT scripting toolset, AWK and Octave programming languages, – combined together for the geospatial data analysis and modelling aimed to study submarine geomorphology of the hadal trench. While traditional geographic data analysis is mostly based on the GIS software, the technical aim of this research is to demonstrate successful application of the advanced tools of data analysis applied for the geospatial research: AWK and Octave are traditionally used in the IT domains, while geological mapping is mostly based on GIS
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