| Author: | J.F. Doyon |
|---|---|
| Contact: | jdoyon at nrcan.gc.ca |
| Author: | Howard Butler |
| Contact: | hobu.inc at gmail.com |
| Revision: | $Revision: 8463 $ |
| Date: | $Date: 2009-01-28 07:37:36 -0800 (Wed, 28 Jan 2009) $ |
Table of Contents
The University of Minnesota’s MapServer is an open-source and freely available map rendering engine for the web. Due to its open-source nature, it can be compiled on a wide variety of platforms and operating systems. We will focus on how to obtain, compile and install MapServer on UNIX-like platforms.
You might also check the MapServerCompilation wiki page for additional information.
You can obtain the MapServer source code as well as the demo package from the Download section.
You can also get the latest MapServer source code from Subversion.
There are a number of issues that you should be aware of when using GD in combination with MapServer.
MapServer aggressively takes advantage of new features and bug fixes in the latest versions of libgd. The minimum required version to run MapServer is 2.0.29. Upgrading to at least 2.0.34 is advised as it includes an important bug fix for antialiased lines. Configure should detect which version of libgd you have installed, but you can quickly check yourself by issuing the following command:
gdlib-config --version
If you intend to use international character sets, your version of libgd must be compiled against the GNU iconv libraries. If you are using a pre-packaged version, it is very likely that this is the case. To check for yourself, issue the following command and look for ‘-liconv’ in the output:
gdlib-config --libs
If you intend to use your system’s libgd, ensure that you have the development package also installed so MapServer can find and use the appropriate headers.
A useful FAQ on for libgd on OSX is available at http://www.libgd.org/DOC_INSTALL_OSX
The GD you compile MapServer against MUST be compiled against the FreeType library in order to use TrueType fonts. MapServer no longer uses it’s own interface to FreeType, using it through GD instead.
When you run your “configure” script, look for the following output:
using GD ( -DUSE_GD_GIF -DUSE_GD_PNG -DUSE_GD_JPEG
-DUSE_GD_WBMP -DUSE_GD_TTF -DGD_HAS_GDIMAGEGIFPTR) from system libs.
If your GD is built against FreeType, you will see either “-DUSE_GD_TTF” (Or “-DUSE_GD_FT” for Freetype 2.x) part. If it’s missing, you will need to recompile your GD to make sure you include FreeType support. See the GD documentation for more information.
Also note that the configure script looks for the FreeType library separately as well, generating output looking somewhat like this:
checking where FreeType is installed...
checking for FT_Init_FreeType in -lfreetype... yes
using libfreetype -lfreetype from system libs.
Even though you have FreeType installed on your system and the configure script finds it, does NOT mean you will have TrueType font support. GD MUST be compiled against FreeType either way.
Versions of libgd earlier than 2.0.34 contain a one very significant bug and will always cause a segfault if you attempt to do one pixel wide antialiasing. You can manually patch older gd’s, or better yet upgrade to at least GD 2.0.34.
In gd.c, function gdImageSetAAPixelColor() change:
int dr,dg,db,p,r,g,b;
p = gdImageGetPixel(im,x,y);
to
int dr,dg,db,p,r,g,b;
if (!gdImageBoundsSafeMacro (im, x, y)) return;
p = gdImageGetPixel(im,x,y);
More detail about this patch (if you need any) was described by Steve Lime in a post to mapserver-users.
ANGLE FOLLOW, a new feature that allows MapServer to draw curved labels about a linear feature like a road, requires libgd 2.0.29 and TrueType font support. Configure should autodetect if you have a sufficient libgd and TrueType support to be able to use this feature.
Since version 5.0 MapServer supports the AGG rendering backend. Download the 2.4 tarball from the antigrain website and just type make in the root directory. If you intend on using mapscript, you must beforehand tweak the agg makefile to add -fPIC to the compiler options.
MapServer provides support for many OGC specifications. At 4.2.3, it provides support for WMS (Web Mapping Service), SLD (Styled Layer Descriptor), WFS (Web Feature Service), and experimental support for WCS (Web Coverage Service).
Support for this specification is automatically enabled when you include PROJ.4 support. (–with-proj) You can check this yourself by looking for the following in your “configure” output:
checking whether we should include WMS support...
OGC WMS compatibility enabled (-DUSE_WMS).
If, for some reason you DON’T want WMS support, you can force it off by passing “–without-wms” to your configure script.
More information on using this feature is available in the WMS Server HOWTO available on the MapServer website.
Cascading is also supported. This allows mapserver to transparently fetch remote layers over WMS, basically acting like a client, and combine them with other layers to generate the final map.
In order to enable this feature, you will need to pass the “–with-wmsclient” option to the configure script. MapServer will automatically look for libcurl, which is also required.
To verify that the WMS Client feature is enabled, check the output from the configure script:
checking whether we should include WMS Client Connections support...
OGC WMS Client Connections enabled (-DUSE_WMS_LYR).
Note that this feature is disabled by default, you have to specifically request it.
More information on using this feature is available in the WMS Client HOWTO available on the MapServer website.
Support for this specification is enabled by passing the configure script the “–with-wfs” option. OGR and PROJ.4 support is required.
You can check this yourself by looking for the following in your “configure” output:
checking whether we should include WFS Server support...
OGC WFS Server support enabled (-DUSE_WFS_SVR).
Note that this feature is disabled by default, you have to specifically request it.
More information on using this feature is available in the WFS Server HOWTO available on the MapServer website.
MapServer can also act as a WFS client. This effectively means that MapServer reads it’s data from a remote server’s WFS output and renders it into a map, just like it would when reading data from a shapefile.
In order to enable this feature, you will need to make sure you include OGR (Built with Xerces support) and PROJ.4 support, and pass the “–with-wfsclient” option to your configure script. MapServer will automatically look for libcurl, which is also required.
To verify that the WFS Client feature is enabled, check the output from the configure script:
checking whether we should include WFS Client Connections support...
OGC WFS Client Connections enabled (-DUSE_WFS_LYR).
Note that this feature is disabled by default, you have to specifically request it.
More information on using this feature is available in the WFS Client HOWTO available on the MapServer website.
MapServer can use a wide variety of sources of data input. One of the solutions growing in popularity is to use spatially enabled databases to store data, and to use them directly to draw maps for the web.
Here you will find out how to enable mapserver to talk to one of these products. Please refer to the MapFile reference for more details on how to use these. This section only details how to compile MapServer for their use.
PostGIS adds support for geographic objects to the PostgreSQL object-relational database. In effect, PostGIS “spatially enables” the PostgreSQL server, allowing it to be used as a backend spatial database for geographic information systems (GIS), much like ESRI’s SDE or Oracle’s Spatial extension. PostGIS is included in many distributions’ packaging system, but you can also roll your own if needed.
MapServer can use PostGIS as a data source. In order to do so simply use “–with-postgis” when running your configure script.
--with-postgis=/usr/local/pgsql/bin/pg_config
MapServer allows you to use SDE as a data source both for geometry and attributes. In order to achieve this, you must have the SDE client librairies at your disposition, and have them installed on the machine running MapServer.
In order to enable SDE support in MapServer, you have to compile it with two options specified:
--with-sde=/opt/sdeexe90
--with-sde-version=90
Oracle’s Spatial Warehousing cartridge is also supported by MapServer. In order to connect to it, you will need to compile MapServer against the Oracle libraries by passing the “–with-oraclespatial” argument to your configure script. You will very likely need an ORACLE_HOME environment variable set to have it configure things correctly.
--with-oraclespatial=/opt/oracle
First prepare the ground by making sure all of your required and/or recommended libraries are installed before attempting to compile MapServer. This will make your life much less complicated ;). Here is the order that I usually use:
Compile GD. This often means acquiring libjpeg, libpng, zlib, and freetype before actually compiling the library. You shouldn’t have too much trouble finding binaries of the libraries that GD requires, and often, they will already be installed with your system. On unix, I’ve had very little luck finding pre-compiled binaries of the required GD library. See libgd section for notes about patching libgd if you plan to use antialiasing.
Compile GDAL/OGR. Describing how to compile GDAL/OGR is beyond the scope of this document. If you have requirements for lots of different formats, make sure to install those libraries first. I often find that building up a GDAL/OGR library often takes as long as compiling MapServer itself!
Compile Proj.4. Proj.4 is a straight-forward configure/make/make install library.
Compile libcurl. libcurl is a straight-forward configure/make/make install library.
Compile/install optional libraries. These might include SDE, PostGIS, Oracle Spatial, AGG, Ming, PDFlib, or MyGIS. Mix and match as you need them.
Unpack the MapServer tarball and cd into the mapserver directory:
[user@host user]$ tar -zxvf mapserver-X.Y.Z.tar.gz
Configure your environment using “configure”. I often place my configure command in its own file and changes its mode to be executable (+x) to save typing and have a record of how MapServer was configured.
./configure --with-sde=/usr/sde/sdeexe90 \
--with-sde-version=90 \
--with-ogr=/usr/local/bin/gdal-config \
--with-gdal=/usr/local/bin/gdal-config \
--with-httpd=/usr/sbin/httpd \
--with-wfsclient \
--with-wmsclient \
--enable-debug \
--with-curl-config=/usr/bin/curl-config \
--with-proj=/usr/local \
--with-tiff \
--with-gd=/usr/local/ \
--with-jpeg \
--with-freetype=/usr/ \
--with-oraclespatial=/usr/oracle \
--with-threads \
--with-wcs \
--with-postgis=/usr/local/database/bin/pg_config \
--with-libiconv=/usr \ # new in 4.8
--with-geos=/usr/local/bin/geos-config \ # new in 4.8
--with-libiconv=/usr \ # new in 4.8
--with-xml2-config=/usr/bin/xml2-config \ # new in 4.10
--with-sos \ # new in 4.10
--with-agg=/path/to/agg-2.4
Now that you have configured your build options and selected all the libraries you wish mapserver to use, you’re ready to compile the source code into an executable.
This is actually quite simple, just execute “make”:
[user@host mapserver]$ make
There is no make install step in the installation of MapServer. The output of the compilation of MapServer is a binary executable that you can use in a CGI execution environment.
To make sure all went well, look for the file called mapserv
[user@host mapserver]$ ls -al mapserv
-rwxr-xr-x 1 user user 351177 Dec 21 11:38 mapserv
A simple test is to try and run it:
[user@host mapserver]$ ./mapserv
This script can only be used to decode form results and
should be initiated as a CGI process via a httpd server.
[user@host mapserver]$
The message above is perfectly normal, and means exactly what it says. If you get anything else, something went terribly wrong.
The MapServer program itself consists of only one file, the “mapserv” binary executable. This is a CGI executable, meant to be called and run by your web server.
In this section, we will assume you are running Apache under its default directory structure in /usr/local/apache. You may need to have privileges to edit your httpd.conf (the main apache configuration file), or have someone (such as your webmaster) help you with the configuration details.
The main goal is to get the “mapserv” binary installed in a publicly accessible directory that is configured to run CGI programs and scripts.
Under a default configuration, the CGI directory is “/usr/local/apache/cgi-bin” (RedHat users will use “/home/httpd/cgi-bin”). Placing the mapserv file in this directory makes it accessible by the following URL: “http://yourhostname.com/cgi-bin/mapserv“. When accessing this URL through your web client, you should expect the following output if all has worked well: “No query information to decode. QUERY_STRING is set, but empty.” If you get this message, you’re done installing MapServer.
The most common problem one is likely to encounter when attempting to install the binary are permissions issues:
You do not have write permissions into your web server’s CGI Directory. Ask your webmaster to install the file for you.
The web server gives you a “403 Permission denied” error. Make sure the user the web server runs as (usually “nobody”) has execute permission on the binary executable. Making the file world executable is perfectly fine and safe:
[user@host cgi-bin]$ chmod o+x mapserv
You may receive a few different type of errors as well if your web server configuration isn’t right:
The An Introduction to MapServer document provides excellent coverage of getting started with MapServer.