Investigation of infinitesimal and finite distortions criteria in the use of Transverse Mercator and Universal Transverse Mercator map projections (Case study: Iran region)
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Fateme Esmaeili , Hamid Mehrabi * , Vahab Nafisi |
University of Isfahan |
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Abstract: (2539 Views) |
Selection of a proper criterion to evaluate map projections' distortions has always been one of the important issues in the field of cartography. One of the classifications for distortions criteria is based on their computational scale. On one hand infinitesimal scale criteria estimate angular and areal distortions based on Tissot indicators, on the other hand finite scale criteria assess shape and areal distortions based on region discretization. In this research, random discretization was replaced with fixed discretization in the computational algorithm of finite scale criteria and the performance of distortions criteria of infinitesimal and finite scale in TM systems and UTM in the study of Iran region was investigated. Although fixed elements remove the limitations of random elements like unrepeatable calculations and lower elements' density in border areas, the results of this study indicate that finite scale criteria are independent of the map projections' characteristics. In order to provide a numerical index for comparing distortions of map projections by averaging the numerical values of criteria, these indexes did not work efficiently in determining the distortions of the projections. Therefore, using only one numerical index to map projections' distortions in regional maps is not significant and it is more reliable to study the pattern of numerical changes of infinitesimal scale criteria to evaluate map projections' distortions in regional maps. According to the results of this study, the numerical range of areal distortions of infinitesimal in the TM projection is up to ten times larger than the UTM system. |
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Keywords: Map projection distortions, Transverse Mercator, Universal Transverse Mercator, Iran region map |
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Full-Text [PDF 1360 kb]
(652 Downloads)
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Type of Study: Research |
Subject:
Geodesy Received: 2022/02/6 | Accepted: 2022/05/7 | ePublished ahead of print: 2022/05/7 | Published: 2022/06/8
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