User guide: Geospatial tools for building footprint and homogeneous zone extraction from GEM Technical Report 2014-01 V1.0.0 imagery Vicini, A., J. Bevington, G. Esquivias, G-C. Iannelli, M. Wieland D ata capture tools GEM GLOBAL EARTHQUAKE MODEL i User guide: Building footprint extraction and definition of homogeneous zone extraction from imagery Technical Report 2014-01 Version: 1.0.0 Date: January 2014 Author(s)*: Vicini, A., J. Bevington, G. Esquivias, G-C. Iannelli and M. Wieland (*) Authors’ affiliations: Alessandro Vicini, ImageCat, UK John Bevington, ImageCat, UK Georgiana Esquivias, ImageCat, Long Beach CA Gianni Cristian Iannelli, University of Pavia, Italy Marc Wieland, GFZ Potsdam, Germany ii Rights and permissions Copyright © 2014 GEM Foundation, Vicini, A., J. Bevington, G. Esquivias, G-C. Iannelli and M. Wieland Except where otherwise noted, this work is licensed under a Creative Commons Attribution 3.0 Unported License. The views and interpretations in this document are those of the individual author(s) and should not be attributed to the GEM Foundation. With them also lies the responsibility for the scientific and technical data presented. The authors have taken care to ensure the accuracy of the information in this report, but accept no responsibility for the material, nor liability for any loss including consequential loss incurred through the use of the material. Citation advice Vicini, A., J. Bevington, G. Esquivias, G-C. Iannelli and M. Wieland (2014), User guide: Building footprint extraction and definition of homogeneous zone extraction from imagery, GEM Technical Report 2014-01 V1.0.0, 243 pp., GEM Foundation, Pavia, Italy, doi: 10.13117/GEM.DATA-CAPTURE.TR2014.01. Photo credits Large cover image: © James Brown, GEM Foundation Small cover image: © Wayne Shelley, British Geological Survey http://www.globalquakemodel.org/ iii ABSTRACT The Global Earthquake Model (GEM) aims to provide a set of tools and models for hazard and risk analysis. The fundamental aim of the GEM Inventory Data Capture Tools (IDCT) risk global component is to provide a set of software and accompanying user protocols to enable users to collect and modify building exposure information, which can be input into the Global Exposure Database and the Global Earthquake Consequences Database. This report describes the tools required to extract building information from remotely-sensed satellite and aerial imagery. It provides a step-by-step user guide for a set of open-source software tools for generating data for the Global Exposure Database. IDCT has proposed an expansive suite of tools for inventory and damage data collection. The opens source image processing and GIS software, Quantum GIS (QGIS) and GRASS provide the core functionality for pre-processing imagery. Algorithms for automatically extracting building footprints are provided as a plug-in toolbar to QGIS. These have evolved from the Building RECognition tool (BREC), developed by the University of Pavia, and have been customised for use in the IDCT suite. Protocols for modifying GIS information are also provided. For regional exposure development, and generating information for use in mapping schemes, areas of homogenous land use can be manually extracted. This can also be achieved in QGIS, however the use of Google Earth for generating these data are also described. A set of sample data are provided to allow users to test the protocols and develop their skills in generating exposure data. More details on this data can be found in Appendix C. Remote sensing provides one of several components for developing exposure information. Additional reports and protocols are available on the GEM website (www.globalquakemodel.org) and NEXUS (www.nexus.globalquakemodel.org) to partner this document, and describe the collection of building inventory and damage information from 1) in-situ field surveys, and 2) mapping schemes. Keywords remote sensing; image processing; building footprint extraction; homogeneous urban area extraction; GIS; inventory development; damage assessment iv TABLE OF CONTENTS Page ABSTRACT ............................................................................................................................................................ iii TABLE OF CONTENTS ........................................................................................................................................... iv LIST OF FIGURES ................................................................................................................................................. vii LIST OF TABLES .................................................................................................................................................. xiv GLOSSARY ........................................................................................................................................................... xv 1 Introduction ..................................................................................................................................................... 1 1.1 Background ............................................................................................................................................. 1 1.2 Aims of this document ............................................................................................................................ 2 1.3 Skills and tools ......................................................................................................................................... 2 1.4 Limitations ............................................................................................................................................... 2 2 Supported Software ........................................................................................................................................ 3 2.1 QuantumGIS 1.7.0 ................................................................................................................................... 3 2.2 GRASS Plug-in .......................................................................................................................................... 3 2.3 BREC4GEM .............................................................................................................................................. 3 2.4 ArcGIS 10 ................................................................................................................................................. 3 2.5 Google Earth ............................................................................................................................................ 4 2.6 ENVI ......................................................................................................................................................... 4 3 Introduction to QuantumGIS and GRASS ........................................................................................................ 5 3.1 QuantumGIS ............................................................................................................................................ 5 3.2 Installation and Sample Data .................................................................................................................. 5 3.3 Graphical User Interface (GUI) ................................................................................................................ 6 3.4 General Setting ........................................................................................................................................ 8 3.5 Coordinate Reference Systems (CRS) ...................................................................................................... 9 3.6 Working with Raster Data ..................................................................................................................... 10 3.7 Working with Vector Data ..................................................................................................................... 12 3.7.1 Creating a new shapefile vector layer ......................................................................................... 13 3.7.2 Digitizing and editing vector data ............................................................................................... 13 3.7.3 Working with the attribute table ................................................................................................ 14 3.8 Plug-in Management ............................................................................................................................. 15 3.9 The GRASS Plug-in ................................................................................................................................. 17 3.10 GRASS Location and Mapset ................................................................................................................. 17 v 3.11 Using GRASS functions in QuantumGIS: the GRASS toolbox ................................................................. 19 3.11.1 Working with GRASS modules using the GRASS Shell ................................................................ 19 3.11.2 Working with GRASS modules using the QuantumGIS Modules Tree/List ................................. 20 3.11.3 Working with the GRASS Location browser ................................................................................ 22 3.12 GRASS Data Import ................................................................................................................................ 23 3.13