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

The Difficulties of Making Maps

If you’ve worked with maps, digital or conventional, you’ll know that despite my enthusiasm, mapping isn’t always easy. Why do we often find it so difficult to make maps of the world around us? How well could you map out the way you normally drive to the supermarket? Usually, it’s easier to describe your trip than it is to draw a map. Perhaps we have a perception of what a map must look like and therefore are afraid to draw our own, thinking it might look silly in comparison. Yet some maps drawn by a friend on a napkin might be of more use than any professional city map could ever be.

Personal Maps

The element of personal knowledge, rather than general knowledge, is what can make a somewhat useful map into one that is very powerful. When words fail to describe the location of something that isn’t general knowledge, a map can round out the picture for you. Maps can be used to supplement a verbal description, but because creating a map involves drawing a perspective from your head, it can be very intimidating. That intimidation and lack of ownership over maps has created an interesting dilemma. In our minds, maps are something that professionals create, not the average person. Yet a map like the one shown in Figure 1-1 can have much more meaning to someone than a professional map of the same area. So what are the professional maps lacking? They show mostly common information and often lack personal information that would make the map more useful or interesting to you.

Technology Barriers

Digital mapping isn’t a new topic. Ever since computers could create graphic representations of the earth, people have been creating maps with them. In early computing, people used to draw with ASCII text-based maps. (I remember creating ASCII maps for role-playing games on a Tandy color computer.) However, designing graphics with ASCII symbols wasn’t pretty. Thankfully, more sophisticated graphic techniques on personal computers allow you to create your own high-quality maps.

A personal map drawn by Ryan Mendenhall showing Chicago Heights, Illinois, U.S.A.; this map is courtesy of Lori Napoleon’s maps project web site:
Figure 1-1. A personal map drawn by Ryan Mendenhall showing Chicago Heights, Illinois, U.S.A.; this map is courtesy of Lori Napoleon’s maps project web site: http://www.subk.net/maps.html

You might already be creating your own maps but aren’t satisfied with the tools. For some, the cost of commercial tools can be prohibitive, especially if you just want to play around for a while to get a feel for the craft. Open source software alleviates the need for immediate, monetary payback on investment.

For others, cost may not be an issue but capabilities are. Just like proprietary software, open source mapping products vary in their features. Improved features might include ease of use or quality of output. One major area of difference is in how products communicate with other products. This is called interoperability and refers to the ability of a program to share data or functions with another program. These often adhere to open standards—protocols for communication between applications. The basic idea is to define standards that aren’t dependent on one particular software package; they would depend instead on the communication process a developer decided to implement. An example of these standards in action is the ability of your program to request maps from another mapping program over the Internet. The real power of open standards is evident when your program can communicate with a program developed by a different group/vendor. This is a crucial issue for many large organizations, especially government agencies, where sharing data across departments can make or break the efficiency in that organization. Products that implement open standards will help to ensure the long-term viability of applications you build. Be warned, however, that some products claim to be interoperable yet stop

short of implementing the full standards. Some companies modify the standards for their product, defeating the purpose of those standards. Interoperability standards are also relatively young and in a state of flux.

Costs and capabilities may not be the main barrier for you. Maybe you want to create your own maps but don’t know how. Maybe you don’t know what tools are available. This book describes some of the free tools available to you, to get you moving toward your end goal of map production.

Another barrier might be that you lack the technical know-how required for digital mapping. While conventional mapping techniques cut out most of the population, digital mapping techniques also prohibit people who aren’t very tech-savvy. This is because installing and customizing software is beyond the scope of many computer users. The good news is that those who are comfortable with the customization side of computerized mapping can create easy-to-use tools for others. This provides great freedom for both parties. Those who have mastered the computer skills involved gain by helping fill other’s needs. New users gain by being able to view mapping information with minimal effort through an existing mapping application.

Technological barriers exist, but for those who can use a computer and want to do mapping with that computer, the possibilities are endless. The mapping tools described here aren’t necessarily easy to use: they require a degree of technical skill. Web mapping programs are more complicated than traditional desktop software. There are often no simple, automated installation procedures, and some custom configuration is required. But in general, once set up, the tools require minimal intervention.