PhD Defence Mr Gaurav Singh

Department of Geo-Information Processing


Title of defence

From location description to map: Understanding VGI from the past


Location plays a fundamental role in human cognition and communication, certainly in this era of social media in which people have freedom to communicate anytime and from anywhere with current communication technology. This opportunity to communicate with text messages or through online social media such as twitter, blogs or facebook allows, for instance, sharing travel experiences.

Geographic Information Systems are well equipped to handle locational information expressed in longitude and latitude, however, they cannot convert the geographic information present in the text to useful map information. Such textual information is known to have existed for over 250 years  with over a billion biological specimens collected, all providing information about the collection locality of the specimen, but not always providing coordinates. This is one of the barriers in using these descriptions for spatial analysis. With some effort of interpretation, one might be able to understand and geocode these locations. Geocoding from textual descriptions is important because it allows to address textual ambiguity and, once the geocoding is done, no other geographic identifier is required.

In a broader perspective the research project reported here aims to understand how humans communicate about location information using semi-structured text and how technology can aid in understanding and spatially representing it. For this purpose, real-world data from the published Ornithological Gazetteer of Brazil was used. In this gazetteer, localities are described using a number of statements that can be interpreted as spatial hints as to position. We identify those hints and their components, which need to be extracted and stored in a structured format. To do so, techniques of natural language processing and information extraction are used to understand the syntactic structure of the descriptions, based on which extraction patterns are developed per hint type. Upon extraction, these hints are translated to spatial representations.

Some hints allow us to represent crisp boundaries as vector representation, whereas others are represented using a probability raster approach. Using these two representation types, hints were converted into their relevant spatial representations and for an entry description, these were combined to derive the common area where the locality at hand is expected to fall. By carrying out this methodology for those entries with available geocodes, we are able to evaluate the accuracy of our results for this gazetteer. The approach presented in the thesis is generic and can be applied to other similar text sources. 


Gaurav Singh received his bachelor's degree in Civil engineering with distinction at North Maharashtra University, India in 2002. After that he worked for SPAN consultant (now a part of SNC-Lavalin group) as a Highway/GIS engineer. In 2003 he joined M.Sc in Geo-Informatics course at Indian Institute of Remote Sensing (IIRS) which was a joint program with International Institute for Geo-Information Science and Earth Observation (ITC). He graduated and obtained ITC M.Sc degree in 2004 with thesis work on "Framework for Location Based Emergency Services in India''. Then he worked first in the capacity of GIS engineer at Rolta India Ltd. working with the Geospatial consultancy department and later as a Technical consultant for Civil and Geo products at Bentley Systems.  In June 2009, after five years of working on various projects for the government and providing training to various organizations, he received funding from European Commission Erasmus Mundus program to pursue PhD at Geo-Information Processing department at ITC.

Singh, G., Kraak, M.J. (promoter) and de By, R.A. (co-promoter) From location description to map : understanding VGI from the past. Enschede, University of Twente Faculty of Geo-Information and Earth Observation (ITC), 2014. (ITC Dissertation 249), ISBN: 978-90-365-3683-7.

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Event starts: Thursday 05 June 2014 at 14:30
Venue: UT Waaier 4
City where event takes place: Enschede
Country where event takes place: Netherlands

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