[mapserver-commits] r8745 - trunk/docs/tutorial

[svn at osgeo.org]

Author: jmckenna
Date: 2009-03-09 17:24:42 -0400 (Mon, 09 Mar 2009)
New Revision: 8745

Added:
   trunk/docs/tutorial/section2.txt
Log:
add ref to section2

Copied: trunk/docs/tutorial/section2.txt (from rev 8689, trunk/docs/tutorial/example1-2.txt)
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--- trunk/docs/tutorial/section2.txt	                        (rev 0)
+++ trunk/docs/tutorial/section2.txt	2009-03-09 21:24:42 UTC (rev 8745)
@@ -0,0 +1,50 @@
+.. _section2:
+
+Section 2: CGI variables and the User Interface
+===============================================
+
+So far we have only looked at the mapfile when creating maps. In creating web mapping 
+applications, it is usually our intention to make maps that can be changed by the user 
+(of the application) interactively. That is, a user should be able to change the content 
+of (or the information in) the map. To accomplish this interactivity, we use the 
+MapServer HTML templates.
+
+A MapServer HTML template is essentially an HTML file with a few MapServer specific tags.
+These tags are the MapServer CGI variables and are enclosed in square brackets "[]". 
+When the MapServer CGI program processes an application, it first parses the query string 
+and the mapfile, and produces the necessary output. Some of this output will need to be 
+written to the HTML template file which you would have to also specify in the mapfile 
+using the web template keyword (or in a separate HTML initialization file). The CGI 
+program will replace all the variables in the HTML template with the proper value 
+before sending it back to the web browser. If you are to directly view an HTML template 
+on a web browser, there won't be any maps rendered and you will instead get blank 
+images and other junk.
+
+MapServer provides several variables for web mapping: the "img" variable which you've 
+seen in Example 1.9 is but one example. There area few core CGI variables originally 
+designed as part of the mapping interface but practically all the mapfile parameters
+can be defined as variables. The definitive reference to the CGI variables can be 
+found at :ref:`here <cgi>`.
+
+We can also define our own variables, which MapServer will pass along to our application. 
+For example, we can create a variable called "root" to represent the root directory of 
+this tutorial, the value for "root" will then be "/tutorial". When the MapServer CGI 
+program processes our HTML template, it will replace every instance of he "[root]" tag 
+with "/tutorial". You will see this in action for each of the following examples.
+
+So, let's build an interactive interface for our application...
+
+- Users of a web mapping application should be able to pan and zoom on the map:
+  `Example 2.1 - Pan and Zoom Controls <http://biometry.gis.umn.edu/cgi-bin/mapserv.exe?map=/ms4w/apps/tutorial/htdocs/example2.map&layer=states&zoom=0&mode=browse&root=/tutorial&program=/cgi-bin/mapserv.exe&map_web=template+example2-1.html>`_  
+
+- They also should be able to turn on and off layers on a map:
+  `Example 2.2 - Layer Control <http://biometry.gis.umn.edu/cgi-bin/mapserv.exe?map=/ms4w/apps/tutorial/htdocs/example2.map&layer=states&zoom=0&mode=browse&root=/tutorial&program=/cgi-bin/mapserv.exe&map_web=template+example2-2.html>`_  
+
+- A map should always include a scalebar.
+  `Example 2.3 - Adding a Scalebar <http://biometry.gis.umn.edu/cgi-bin/mapserv.exe?map=/ms4w/apps/tutorial/htdocs/example2.map&layer=states&zoom=0&mode=browse&root=/tutorial&program=/cgi-bin/mapserv.exe&map_web=template+example2-3.html>`_  
+
+- If users are to navigate through the map, a reference map should be provided:
+  `Example 2.4 - Adding a Reference Map <http://biometry.gis.umn.edu/cgi-bin/mapserv.exe?map=/ms4w/apps/tutorial/htdocs/example2.map&layer=states&zoom=0&mode=browse&root=/tutorial&program=/cgi-bin/mapserv.exe&map_web=template+example2-4.html>`_  
+
+- The map should include a legend.
+  `Example 2.5- Adding a Legend <http://biometry.gis.umn.edu/cgi-bin/mapserv.exe?map=/ms4w/apps/tutorial/htdocs/example2.map&layer=states&zoom=0&mode=browse&root=/tutorial&program=/cgi-bin/mapserv.exe&map_web=template+example2-5.html>`_  
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