Changes in VGI Quality Over Time: Positional Accuracy Trends in Tehran City

Document Type : Original Article

Authors

1 School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran, Tehran, Iran

2 School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran

3 Sahand University of Technology

10.22059/eoge.2024.381041.1157

Abstract

The growing use of Volunteered Geographic Information (VGI), including data from OpenStreetMap (OSM), raises concerns about data quality due to variations in contributors' skills and tools. This study assesses the positional accuracy of voluntary features in Tehran by comparing them with official datasets. A feature matching approach using Hausdorff distance, orientation difference, and buffer overlap, normalized through fuzzy logic, was used to evaluate accuracy. Preprocessing steps included standardizing data extent and coordinate systems, correcting topological errors, and converting datasets into graph structures. Results show that most voluntary features had high positional accuracy, with over 87% achieving positional accuracy above 82%. Temporal analysis revealed peaks in voluntary contributions in 2012 and 2017, but a slight overall decline in positional accuracy from 2007 to 2022, indicated by a negative trend line slope of -0.001834. This study introduces a method for assessing historical data accuracy using feature matching across a large area like Tehran to track positional accuracy trends over time. It underscores the need for extrinsic assessment in VGI, noting that technological advancements do not always lead to improved positional accuracy. The comprehensive approach in this study offers insights into VGI quality and reliability.

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Main Subjects

Earth Observation and Geomatics Engineering
Volume 7, Issue 2
December 2023

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