Table of Contents for
Web Mapping Illustrated

Version ebook / Retour

Cover image for bash Cookbook, 2nd Edition Web Mapping Illustrated by Tyler Mitchell Published by O'Reilly Media, Inc., 2005
  1. Web Mapping Illustrated
  2. Cover
  3. Web Mapping Illustrated
  4. A Note Regarding Supplemental Files
  5. Foreword
  6. Preface
  7. Youthful Exploration
  8. The Tools in This Book
  9. What This Book Covers
  10. Organization of This Book
  11. Conventions Used in This Book
  12. Safari Enabled
  13. Comments and Questions
  14. Acknowledgments
  15. 1. Introduction to Digital Mapping
  16. 1.1. The Power of Digital Maps
  17. 1.2. The Difficulties of Making Maps
  18. 1.3. Different Kinds of Web Mapping
  19. 2. Digital Mapping Tasks and Tools
  20. 2.1. Common Mapping Tasks
  21. 2.2. Common Pitfalls, Deadends, and Irritations
  22. 2.3. Identifying the Types of Tasks for a Project
  23. 3. Converting and Viewing Maps
  24. 3.1. Raster and Vector
  25. 3.2. OpenEV
  26. 3.3. MapServer
  27. 3.4. Geospatial Data Abstraction Library (GDAL)
  28. 3.5. OGR Simple Features Library
  29. 3.6. PostGIS
  30. 3.7. Summary of Applications
  31. 4. Installing MapServer
  32. 4.1. How MapServer Applications Operate
  33. 4.2. Walkthrough of the Main Components
  34. 4.3. Installing MapServer
  35. 4.4. Getting Help
  36. 5. Acquiring Map Data
  37. 5.1. Appraising Your Data Needs
  38. 5.2. Acquiring the Data You Need
  39. 6. Analyzing Map Data
  40. 6.1. Downloading the Demonstration Data
  41. 6.2. Installing Data Management Tools: GDAL and FWTools
  42. 6.3. Examining Data Content
  43. 6.4. Summarizing Information Using Other Tools
  44. 7. Converting Map Data
  45. 7.1. Converting Map Data
  46. 7.2. Converting Vector Data
  47. 7.3. Converting Raster Data to Other Formats
  48. 8. Visualizing Mapping Data in a Desktop Program
  49. 8.1. Visualization and Mapping Programs
  50. 8.2. Using OpenEV
  51. 8.3. OpenEV Basics
  52. 9. Create and Edit Personal Map Data
  53. 9.1. Planning Your Map
  54. 9.2. Preprocessing Data Examples
  55. 10. Creating Static Maps
  56. 10.1. MapServer Utilities
  57. 10.2. Sample Uses of the Command-Line Utilities
  58. 10.3. Setting Output Image Formats
  59. 11. Publishing Interactive Maps on the Web
  60. 11.1. Preparing and Testing MapServer
  61. 11.2. Create a Custom Application for a Particular Area
  62. 11.3. Continuing Education
  63. 12. Accessing Maps Through Web Services
  64. 12.1. Web Services for Mapping
  65. 12.2. What Do Web Services for Mapping Do?
  66. 12.3. Using MapServer with Web Services
  67. 12.4. Reference Map Files
  68. 13. Managing a Spatial Database
  69. 13.1. Introducing PostGIS
  70. 13.2. What Is a Spatial Database?
  71. 13.3. Downloading PostGIS Install Packages and Binaries
  72. 13.4. Compiling from Source Code
  73. 13.5. Steps for Setting Up PostGIS
  74. 13.6. Creating a Spatial Database
  75. 13.7. Load Data into the Database
  76. 13.8. Spatial Data Queries
  77. 13.9. Accessing Spatial Data from PostGIS in Other Applications
  78. 14. Custom Programming with MapServer’s MapScript
  79. 14.1. Introducing MapScript
  80. 14.2. Getting MapScript
  81. 14.3. MapScript Objects
  82. 14.4. MapScript Examples
  83. 14.5. Other Resources
  84. 14.6. Parallel MapScript Translations
  85. A. A Brief Introduction to Map Projections
  86. A.1. The Third Spheroid from the Sun
  87. A.2. Using Map Projections with MapServer
  88. A.3. Map Projection Examples
  89. A.4. Using Projections with Other Applications
  90. A.5. References
  91. B. MapServer Reference Guide for Vector Data Access
  92. B.1. Vector Data
  93. B.2. Data Format Guide
  94.  
  95. ESRI Shapefiles (SHP)
  96.  
  97. PostGIS/PostgreSQL Database
  98.  
  99. MapInfo Files (TAB/MID/MIF)
  100.  
  101. Oracle Spatial Database
  102.  
  103. Web Feature Service (WFS)
  104.  
  105. Geography Markup Language Files (GML)
  106.  
  107. VirtualSpatialData (ODBC/OVF)
  108.  
  109. TIGER/Line Files
  110.  
  111. ESRI ArcInfo Coverage Files
  112.  
  113. ESRI ArcSDE Database (SDE)
  114.  
  115. Microstation Design Files (DGN)
  116.  
  117. IHO S-57 Files
  118.  
  119. Spatial Data Transfer Standard Files (SDTS)
  120.  
  121. Inline MapServer Features
  122.  
  123. National Transfer Format Files (NTF)
  124. About the Author
  125. Colophon
  126. Copyright

Name

Geography Markup Language Files (GML)

Synopsis

  • Also known as Geographic Markup Language and GML/XML.

  • GML is a text-based, XML format that can represent vector and attribute data.

  • This is an Open Geospatial Consortium specification for data interchange.

File listing

GML files are usually a single text file with a GML filename extension (coal_dep.gml). Some may use XML as the filename extension.

XML schema documents often accompany GML files that have been translated from some other format (e.g., using the ogr2ogr utility).

Example of text in a GML file

GML uses sets of nested tags to define attributes and geometry coordinates:

      <gml:featureMember>
        <Coal_Deposits fid="1">
          <UNKNOWN>0.000</UNKNOWN>
          <NA>0.000</NA>
          <ID>2</ID>
          <ID2>2</ID2>
          <MARK>7</MARK>
          <COALKEY>110</COALKEY>
          <COALKEY2>110</COALKEY2>
          <ogr:geometryProperty>
            <gml:Point>
              <gml:coordinates>78.531,50.694</gml:coordinates>
            </gml:Point>
          </ogr:geometryProperty>
        </Coal_Deposits>
      </gml:featureMember>

Data access/connection method

  • GML access is available in MapServer through OGR.

  • The CONNECTIONTYPE OGR parameter must be used.

  • The path to the GML file is required, including a file extension.

  • There can be multiple layers in a GML file, including multiple feature types.

ogrinfo examples

Here’s an example that uses ogrinfo on a single GML file:

                  > ogrinfo /data/gml/coal_dep.gml
    Had to open data source read-only.
    INFO: Open of 'coal_dep.gml'
    using driver 'GML' successful.
    1: Coal_Deposits

Here’s an example that uses ogrinfo to examine the structure of one layer:

                  > ogrinfo -summary /data/gml/coal_dep.gml Coal_Deposits
    Had to open data source read-only.
    INFO: Open of 'coal_dep.gml'
    using driver 'GML' successful.
     
    Layer name: Coal_Deposits
    Geometry: Unknown (any)
    Feature Count: 266
    Extent: (23.293650, 37.986340) - (179.272550, 80.969670)
    Layer SRS WKT:
    (unknown)
    UNKNOWN: Real (0.0)
    NA: Real (0.0)
    ID: Integer (0.0)
    ID2: Integer (0.0)
    MARK: Integer (0.0)
    COALKEY: Integer (0.0)
    COALKEY2: Integer (0.0)
    LONG: Real (0.0)
    LAT: Real (0.0)

Map file example

    LAYER
      NAME coal_deposits
      TYPE POINT
      STATUS DEFAULT
      CONNECTIONTYPE OGR
      CONNECTION "gml/coal_dep.gml"
      CLASS
        COLOR 0 0 0
        SYMBOL 'circle'
        SIZE 6
      END
    END