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

Web Feature Service (WFS)

Synopsis

WFS is an Open Geospatial Consortium specification. For more information about the format itself, see http://www.opengeospatial.org/.

WFS allows a client to retrieve geospatial data encoded in Geography Markup Language (GML) from multiple Web Feature Services. GML is built on the standard web language XML.

WFS differs from the popular Web Map Service specification in that WFS returns a subset of the data in valid GML format, not just a graphic image of data.

Capabilities

Requesting capabilities using the GetCapabilities request to a WFS server returns an XML document showing what layers and projections are available, etc.

Example of a WFS GetCapabilities URL

    http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap
    ?VERSION=1.0.0
    &SERVICE=wfs
    &REQUEST=GetCapabilities

Example of the resulting XML from GetCapabilties

Example B-1. Resulting XML from GetCapabilities
...
<FeatureTypeList>
 <Operations>
  <Query/>
 </Operations>
   <FeatureType>
    <Name>park</Name>
    <Title>Parks</Title>
    <SRS>EPSG:42304</SRS>
    <LatLongBoundingBox minx="-173.433" miny="41.4271" maxx="-13.0481" maxy="83.7466" />
  </FeatureType>
  <FeatureType>
    <Name>road</Name>
    <Title>Roads</Title>
    <SRS>EPSG:42304</SRS>
    <LatLongBoundingBox minx="-148.059" miny="35.882" maxx="-33.7745" maxy="72.5503" />
   </FeatureType>
   <FeatureType>
     <Name>popplace</Name>
     <Title>Cities</Title>
     <SRS>EPSG:42304</SRS>
     <LatLongBoundingBox minx="-172.301" miny="36.3541" maxx="-12.9698" maxy="83.4832" />
 </FeatureType>
 </FeatureTypeList>
...

Data access/connection method

  • WFS access is a core MapServer feature.

  • MapServer currently supports WFS Version 1.0.0.

  • The CONNECTIONTYPE WFS parameter must be used.

WFS layers can be requested through a layer in a map file, or you can request the GML directly through the browser with a GetFeature request. You can specify a specific layer with the TypeName request. In a map file, the name/value pairs should be put into a METADATA object.

You can limit the number of features returned in the GML by using the MaxFeatures option (e.g., &MAXFEATURES=100).

Example of a WFS request directly through the browser

The following URL requests the GML for the layer road (see the earlier section, "Capabilities,” for the possible layers available on this test server). The URL is all one line, broken up here for readability.

    http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap
    ?VERSION=1.0.0
    &SERVICE=wfs
    &REQUEST=getfeature&TYPENAME=road

Map file example

    LAYER
      NAME "wfs_gmap_roads"
      STATUS DEFAULT
      TYPE LINE
      CONNECTIONTYPE WFS
      CONNECTION "http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap?
      METADATA
        "wfs_version" "1.0.0"
        "wfs_srs" "EPSG:42304"
        "wfs_typename" "road"
        "wfs_request_method" "GET"
        "wfs_service" "WFS"
      END
      CLASS
        NAME "roads"
        COLOR 0 0 0
      END
    END  # layer