Home | Docs | Issue Tracker | FAQ | Download
MapServer logo

Table Of Contents

Previous topic

OGC Support and Configuration

Next topic

WMS Client

This Page

Quick search

Enter search terms or a module, class or function name.

WMS Server

Author:Jeff McKenna
Contact:jmckenna at gatewaygeomatics.com
Revision:$Revision: 8374 $
Date:$Date: 2009-01-02 07:09:01 -0800 (Fri, 02 Jan 2009) $
Last Updated:2006/01/09

Introduction

A WMS (or Web Map Server) allows for use of data from several different servers, and enables for the creation of a network of Map Servers from which clients can build customized maps. The following documentation is based on the Open Geospatial Consortium’s (OGC) Web Map Server Interfaces Implementation Specification v1.1.1.

MapServer v3.5 or more recent is required to implement WMS features. At the time this document was written, MapServer supports the following WMS versions: 1.0.0, 1.0.7, 1.1.0 (a.k.a. 1.0.8), and 1.1.1.

This document assumes that you are already familiar with certain aspects of MapServer:

  • MapServer application development and setting up .map files.
  • Familiarity with the WMS spec would be an asset. A link to the WMS specification document is included in the “WMS-Related Information” section below.

How does a WMS Work

WMS servers interact with their clients via the HTTP protocol. In most cases, a WMS server is a CGI program. This is also the case with MapServer.

The WMS specification defines a number of request types, and for each of them a set of query parameters and associated behaviors. A WMS-compliant server MUST be able to handle at least the following 2 types of WMS requests:

  1. GetCapabilities: return an XML document with metadata of the Web Map Server’s information
  2. GetMap: return an image of a map according to the user’s needs.

And support for the following types is optional:

  1. GetFeatureInfo: return info about feature(s) at a query (mouse click) location. MapServer supports 3 types of responses to this request:
    • text/plain output with attribute info.
    • text/html output using MapServer query templates specified in the CLASS template parameter. The MIME type returned by the Class templates defaults to text/html and can be controlled using the metadata “wms_feature_info_mime_type”.
    • application/vnd.ogc.gml, GML.1 or GML for GML features.
  2. DescribeLayer: return an XML description of one or more map layers. To execute this:
    • for vector layers: to have a valid return the user needs to setup wfs_onlineresource (or ows_onlineresource) metadata either at the map level or at the layer level (the layer level metadata is the one which is used if both are defined)
    • for raster layers: the metadata is wcs_onlineresource with the same logic as above.
  3. GetLegendGraphic: returns a legend image (icon) for the requested layer, with label(s). More information on this request can be found in the GetLegendGraphic section later in this doc.

With respect to MapServer specifically, it is the “mapserv” CGI program that knows how to handle WMS requests. So setting up a WMS server with MapServer involves installing the mapserv CGI program and a setting up a mapfile with appropriate metadata in it. This is covered in the rest of this document.

Setting Up a WMS Server Using MapServer

Install the Required Software

WMS requests are handled by the mapserv CGI program. Not all versions of the mapserv program do include WMS support (it is included by default when you compile together with the PROJ library), so the first step is to check that your mapserv executable includes WMS support. One way to verify this is to use the “-v” command-line switch and look for “SUPPORTS=WMS_SERVER”.

(Unix users should refer to the Compiling on Unix document for any compiling instructions, and Windows users might want to use MS4W, which comes ready with WMS/WFS support)

Example 1. On Unix:

$ ./mapserv -v
MapServer version 4.6.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=PDF
OUTPUT=SWF OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER
SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER
INPUT=JPEG INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG

Example 2. On Windows:

C:\apache\cgi-bin> mapserv -v
MapServer version 4.6.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=PDF
OUTPUT=SWF OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER
SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER
INPUT=JPEG INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG

Setup a Mapfile For Your WMS

Each instance of WMS server that you setup needs to have its own mapfile. It is just a regular MapServer mapfile in which some parameters and some metadata entries are mandatory. Most of the metadata is required in order to produce a valid GetCapabilites output.

Here is the list of parameters and metadata items that usually optional with MapServer, but are required (or strongly recommended) for a WMS configuration:

At the MAP level:

  • Map NAME
  • Map PROJECTION
  • Map Metadata (in the WEB Object):
    • wms_title
    • wms_onlineresource
    • wms_srs (unless PROJECTION object is defined using “init=epsg:...”)

And for each LAYER:

  • Layer NAME
  • Layer PROJECTION
  • Layer METADATA
    • wms_title
    • wms_srs (optional since the layers inherit the map’s SRS value)
  • Layer STATUS
    • Layers set to STATUS DEFAULT will always be sent to the client.
    • Layers set to STATUS ON or STATUS OFF can be requested by the client.
  • Layer TEMPLATE (required for GetFeatureInfo requests)
  • Layer DUMP TRUE (only required for GetFeatureInfo GML requests)

Let’s go through each of these paramters in more detail:

  • Map Name and wms_title:

    WMS Capabilities requires a Name and a Title tag for every layer. The Map’s NAME and wms_title metadata will be used to set the root layer’s name and title in the GetCapabilities XML output. The root layer in the WMS context corresponds to the whole mapfile.

  • Layer Name and wms_title metadata:

    Every individual layer needs its own unique name and title. Layer names are also used in GetMap and GetFeatureInfo requests to refer to layers that should be included in the map output and in the query. Layer names must start with a letter when setting up a WMS server (layer names should not start with a digit or have spaces in them).

  • Map PROJECTION and wms_srs metadata:

    WMS servers have to advertise the projection in which they are able to serve data using EPSG projection codes (see http://www.epsg.org/ for more background on EPSG codes). Recent versions of the PROJ4 library come with a table of EPSG initialization codes and allow users to define a projection like this:

    PROJECTION
       "init=epsg:4269"
    END
    

    (Note that “epsg” has to be in lowercase when used in the PROJ4 ‘init’ directive.)

    If the MAP PROJECTION block is provided in the format “init=epsg:xxxx” then MapServer will also use this information to generate a <BoundingBox> tag for the top-level layer in the WMS capabilities document. Note that the BoundingBox is an optional element of WMS capabilities, but it is good practice to allow MapServer to include it when possible.

    The above is sufficient for MapServer to recognize the EPSG code and include it in SRS tags in the capabilities output (wms_srs metadata is not required in this case). However, it is often impossible to find an EPSG code to match the projection of your data. In those cases, the “wms_srs” metadata is used to list one or more EPSG codes that the data can be served in, and the PROJECTION object contains the real PROJ4 definition of the data’s projection.

    Here is an example of a server whose data is in an Lambert Conformal Conic projection (42304). It’s capabilities output will advertize EPSG:4269 and EPSG:4326 projections (lat/lon), but the PROJECTION object is set to the real projection that the data is in:

    NAME "DEMO"
    ...
    
    WEB
      ...
      METADATA
        "wms_title"           "WMS Demo Server"
        "wms_onlineresource"  "http://my.host.com/cgi-bin/mapserv?map=wms.map&"
        "wms_srs"             "EPSG:4269 EPSG:4326"
      END
    END
    
    PROJECTION
      "init=epsg:42304"
    END
    ...
    END
    

    In addition to EPSG:xxxx projections, a WMS server can advertize projections in the AUTO:xxxx namespace. AUTO projections 42001 to 42005 are internally supported by MapServer. However, AUTO projections are useful only with smart WMS clients, since the client needs to define the projection parameters in the WMS requests to the server. For more information see Annex E of the WMS 1.1.1 specification and section 6.5.5.2 of the same document. See also the FAQ on AUTO projections at the end of this document.

  • Layer PROJECTION and wms_srs metadata:

    By default layers inherit the SRS of their parent layer (the map’s PROJECTION in the MapServer case). For this reason it is not necessary (but still strongly recommended) to provide PROJECTION and wms_srs for every layer. If a layer PROJECTION is not provided then the top-level map projecion will be assumed.

    Layer PROJECTION and wms_srs metadata are defined exactly the same way as the map’s PROJECTION and wms_srs metadata.

    For vector layers, if a PROJECTION block is provided in the format “init=epsg:xxxx” then MapServer will also use this information to generate a <BoundingBox> tag for this layer in the WMS capabilities document. Note that the BoundingBox is an optional element of WMS capabilities, but it is good practice to allow MapServer to include it when possible.

  • “wms_onlineresource” metadata:

    The wms_onlineresource metadata is set in the map’s web object metadata and specifies the URL that should be used to access your server. This is required for the GetCapabilities output. If wms_onlineresource is not provided then MapServer will try to provide a default one using the script name and hostname, but you shouldn’t count on that too much. It is strongly recommended that you provide the wms_onlineresource metadata.

    See section 6.2.2 of the WMS 1.1.1 specification for the whole story about the online resource URL. Basically, what you need is a complete HTTP URL including the http:// prefix, hostname, script name, potentially a “map=” parameter, and and terminated by “?” or “&”.

    Here is a valid online resource URL:

    http://my.host.com/cgi-bin/mapserv?map=mywms.map&

    By creating a wrapper script on the server it is possible to hide the “map=” parameter from the URL and then your server’s online resource URL could be something like:

    http://my.host.com/cgi-bin/mywms?

    This is covered in more detail in the section “More About the Online Resource URL” below.

  • Configuring for GetFeatureInfo Requests:

    You must set the layer TEMPLATE parameter for the layer to be queryable by GetFeatureInfo requests. For requests of type “text/html” you should also set the layer HEADER and FOOTER parameters.

    For GetFeatureInfo requests of GML you must set the layer to DUMP TRUE in the mapfile. As of MapServer 4.6 you must also set the gml_* metadata for the layer attributes to be served (see the Layer Object metadata in the Reference Section later in this document).

    Here are working examples of GetFeatureInfo requests: text/plain / text/html / gml (for gml, your browser might ask you to save the file, if so save it locally as a .gml file and view it in a text editor)

Test Your WMS Server

Validate the Capabilities Metadata

OK, now that we’ve got a mapfile, we have to check the XML capabilities returned by our server to make sure nothing is missing.

Using a web browser, access your server’s online resource URL to which you add the parameters “SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities” to the end, e.g.

http://my.host.com/cgi-bin/mapserv?map=mywms.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities

Here is a working GetCapabilities request (note that the SERVICE parameter is required for all GetCapabilities requests):

http://www2.dmsolutions.ca/cgi-bin/mswms_gmap?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities

This should return a document of MIME type application/vnd.ogc.wms_xml, so your browser is likely going to prompt you to save the file. Save it and open it in a text editor (Emacs, Notepad, etc.), and you will see the returned XML from the WMS server.

If you get an error message in the XML output then take necessary actions. Common problems and solutions are listed in the FAQ at the end of this document.

If everything went well, you should have a complete XML capabilities document. Search it for the word “WARNING”... MapServer inserts XML comments starting with “<!–WARNING: ” in the XML output if it detects missing mapfile parameters or metadata items. If you notice any warning in your XML output then you have to fix all of them before you can register your server with a WMS client, otherwise things are likely not going to work.

Note that when a request happens, it is passed through WMS, WFS, and WCS in MapServer (in that order) until one of the services respond to it.

Test With a GetMap Request

OK, now that we know that our server can produce a valid XML GetCapabilities response we should test the GetMap request. MapServer only checks for a few of the required GetMap parameters, so both of the minimum MapServer parameters and a valid GetMap request will be explained below.

The following is a list of the required GetMap parameters according to the WMS spec:

VERSION=version: Request version

REQUEST=GetMap: Request name

LAYERS=layer_list: Comma-separated list of one or more map layers. Optional if SLD parameter is present.

STYLES=style_list: Comma-separated list of one rendering style per requested layer. Optional if SLD parameter is present. NOTE that MapServer does not support named styles, so most times you would specify “STYLES=” with an empty value. MapServer does support STYLES when used with an SLD.

SRS=namespace:identifier: Spatial Reference System.

BBOX=minx,miny,maxx,maxy: Bounding box corners (lower left, upper right) in SRS units.

WIDTH=output_width: Width in pixels of map picture.

HEIGHT=output_height: Height in pixels of map picture.

FORMAT=output_format: Output format of map.

Note

WMS Servers only advertise supported formats that are part of the gd / gdal libraries.

A valid example would therefore be:

http://my.host.com/cgi-bin/mapserv?map=mywms.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&LAYERS=prov_bound&STYLES=&SRS=EPSG:4326&BBOX=-173.537,35.8775,-11.9603,83.8009&WIDTH=400&HEIGHT=300&FORMAT=image/png

Here is a working valid request.

Test with a Real Client

If you have access to a WMS client, then register your new server’s online resource with it and you should be off and running.

If you don’t have your own WMS client installed already, here are a few pointers:

  • MapServer itself can be used as a WMS client, see the MapServer WMS Client Howto.
  • Deegree provides a WMS client.
  • MapLab’s MapBrowser is a web-based WMS client.
  • OpenJUMP is a desktop GIS package which includes WMS client support.
  • owsview Viewer Client Generator is an online application that allows users to add WMS layers.
  • uDig is a desktop package that allows users to add WMS layers.

This list is not exhaustive, there are several Open Source or proprietary packages that offer WMS support and could be used to interact with your new MapServer WMS server instance.

More About the Online Resource URL

As mentioned in the section “Setup a Mapfile / wms_onlineresource metadata” above, the following Online Resource URL is perfectly valid for a MapServer WMS according to section 6.2.2 or the WMS 1.1.1 specification:

http://my.host.com/cgi-bin/mapserv?map=mywms.map&

However, some people will argue that the above URL contains mandatory vendor-specific parameters and that this is illegal. First we would like to point that “map=...” is not considered a vendor-specific parameter in this case since it is part of the Online Resource URL which is defined as an opaque string terminated by “?” or “&” (See WMS 1.1.1 section 6.2.2).

But anyway, even if it’s valid, the above URL is still ugly. And you might want to use a nicer URL for your WMS Online Resource URL. Here are some suggestions:

  1. On Unix servers, you can setup a wrapper shell script that sets the MS_MAPFILE environment variable and then passes control to the mapserv executable... that results on a cleaner OnlineResource URL:
#! /bin/sh
MS_MAPFILE=/path/to/demo.map
export MS_MAPFILE
/path/to/mapserv
  1. Another option is to use the “setenvif” feature of Apache: use symbolic links that all point to a same mapserv binary, and then for each symbolic link test the url, and set the MAP environment accordingly.

    For Windows and Apache users the steps are as follows (this requires Apache 1.3 or newer):

    • Copy mapserv.exe to a new name for your WMS, such as “mywms.exe”.

    • In httpd.conf, add:

      SetEnvIf Request_URI "/cgi-bin/mywms" MS_MAPFILE=/path/to/mymap.map
  2. On IIS servers (Windows), you can use the following ASP script:

    Note

    The script below, while functional, is intended only as an example of using ASP to filter MapServer requests. Using ASP in a production WMS server will likely require additional ASP especially in the area of error handling and setting timeouts.*

    <%
      Server.ScriptTimeout = 360
    
      Select Case Request.ServerVariables("REQUEST_METHOD")
        Case "GET"  strRequest = Request.QueryString
        Case "POST" strRequest = Request.Form
      End Select
    
      strURL = "http://myserver/cgi-bin/mapserv.exe?map=C:\Inetpub\wwwroot\workshop\itasca.map&" & strRequest
    
      Dim objHTTP
      Set objHTTP = Server.CreateObject("MSXML2.ServerXMLHTTP")
      objHTTP.open "GET", strURL, false
      objHTTP.send ""
    
      Response.ContentType = objHTTP.getResponseHeader("content-type")
      Response.BinaryWrite objHTTP.responseBody
    
      Set objHTTP = Nothing
    %>
    

GetLegendGraphic Request

This request returns a legend image (icon) for the specified layer. The request will draw an icon and a label for all classes defined on the layer.

Requirements

The following are required in the WMS server mapfile to enable this request:

  • a LEGEND object.
  • a CLASS object for each layer.
  • a NAME in the CLASS object.
  • the STATUS of each LAYER must be set to ON.

Parameters

The following are valid parameters for this request:

  • LAYER - (Required) Name of the WMS layer to return the legend image of. Note that this is the <Name> parameter of the Layer in the GetCapabilities.
  • FORMAT - (Required) Format of the legend image (e.g. “image/png”).
  • WIDTH - (Optional) Width of the legend image. Note that the Width parameter is only used when the Rule parameter is also used in the request.
  • HEIGHT - (Optional) Height of the legend image. Note that the Height parameter is only used when the Rule parameter is also used in the request.
  • SLD - (Optional) The URL to the SLD. Applies the SLD on the layer and the legend is drawn after the SLD is applied (using the classes specfied by the SLD). Note here that you need to put a <Name>class1</Name> inside the Rule element so that a class name is created from the SLD and therefore a correct legend image.
  • SLD_BODY - (Optional) The body (code) of the SLD, instead of specifying a URL (as in the ‘SLD’ parameter).
  • SCALE - (Optional) Specify a scale so that only layers that fall into that scale will have a legend.
  • RULE - (Optional) Specify the name of the CLASS to generate the legend image for (as opposed to generating an icon and label for ALL classes for the layer).

Note

All rules that are used to draw the legend in normal CGI mode apply here. See the CGI Reference doc if necessary.

The CLASS object’s KEYIMAGE parameter can also be used to specify a legend image for a CLASS. See the MapFile Reference doc if necessary. Example Request

An example request might look like:

http://127.0.0.1/cgi-bin/mapserv.exe?SERVICE=WMS&VERSION=1.1.1&layer=park&
REQUEST=getlegendgraphic&FORMAT=image/png

Reference Section

The following metadata are available in the setup of the mapfile:

(Note that each of the metadata below can also be referred to as ‘ows_*’ instead of ‘wms_*’. MapServer tries the ‘wms_*’ metadata first, and if not found it tries the corresponding ‘ows_*’ name. Using this reduces the amount of duplication in mapfiles that support multiple OGC interfaces since “ows_*” metadata can be used almost everywhere for common metadata items shared by multiple OGC interfaces.)

Web Object Metadata

ows_http_max_age

  • Description: (Optional) an integer (in seconds) to specify how long a given map response should be considered new. Setting this directive allows for aware WMS clients to use this resulting HTTP header value as a means to optimize (and minimize) requests to a WMS Server. More info is available at http://www.mnot.net/cache_docs/#CACHE-CONTROL

ows_updatesequence

  • Description: (Optional) The updateSequence parameter can be used for maintaining the consistency of a client cache of the contents of a service metadata document. The parameter value can be an integer, a timestamp in [ISO 8601:2000] format, or any other number or string.

ows_schemas_location

  • Description: (Optional) (Note the name ows_schemas_location and not wms_... this is because all OGC Web Services (OWS) use the same metadata) Root of the web tree where the family of OGC WMS XMLSchema files are located. This must be a valid URL where the actual .xsd files are located if you want your WMS output to validate in a validating XML parser. Default is http://schemas.opengeospatial.net. See http://ogc.dmsolutions.ca for an example of a valid schema tree.

wms_abstract

  • WMS TAG Name: Abstract (WMS1.1.1, sect. 7.1.4.2)
  • Description: (Optional) A blurb of text providing more information about the WMS server.

wms_accessconstraints

  • WMS TAG Name: AccessConstraints (WMS1.1.1, sect. 7.1.4.2)
  • Description: (Optional) Access constraints information. Use the reserved word “none” if there are no access constraints.

wms_addresstype, wms_address, wms_city, wms_stateorprovince, wms_postcode, wms_country

  • WMS TAG Name: ContactAddress and family (WMS1.1.1, sect. 7.1.4.2)
  • Description: Optional contact address information. If provided then all six metadata items are required.

wms_attribution_logourl_format

  • Description: (Optional) The MIME type of the logo image. (e.g. “image/png”). Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_height

  • Description: (Optional) Height of the logo image in pixels. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_href

  • Description: (Optional) URL of the logo image. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_width

  • Description: (Optional) Width of the logo image in pixels. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_onlineresource

  • Description: (Optional) The data provider’s URL.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_title

  • Description: (Optional) Human-readable string naming the data provider.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_contactelectronicmailaddress

  • WMS TAG Name: ContactElectronicMailAddress (WMS1.1.1, sect. 7.1.4.2)
  • Description: Optional contact Email address.

wms_contactfacsimiletelephone

  • WMS TAG Name: ContactFacsimileTelephone (WMS1.1.1, sect. 7.1.4.2)
  • Description: Optional contact facsimile telephone number.

wms_contactperson, wms_contactorganization, wms_contactposition

  • WMS TAG Name: ContactInformation, ContactPerson, ContactOrganization, ContactPosition (WMS1.1.1, sect. 7.1.4.2)
  • Description: Optional contact information. If provided then all three metadata items are required.

wms_contactvoicetelephone

  • WMS TAG Name: ContactVoiceTelephone (WMS1.1.1, sect. 7.1.4.2)
  • Description: Optional contact voice telephone number.

wms_encoding

  • WMS TAG Name: Encoding
  • Description: Optional XML capabilities encoding type. The default is ISO-8859-1.

wms_feature_info_mime_type

  • WMS TAG Name: Feature_info_mime_type

  • Description:

    • Used to specify an additional MIME type that can be used when responding to the GetFeature request.

      For example if you want to use the layer’s HTML template as a base for its response, you need to add “WMS_FEATURE_INFO_MIME_TYPE” “text/html”. Setting this will have the effect of advertizing text/html as one of the MIME types supported for a GetFeature request. You also need to make sure that the layer points to a valid html template. The client can then call the server with INFO_FORMAT=text/html.

    • If not specified, MapServer by default has text/plain and GML implemented.

    • Note that for GML to be returned the layer in the wms-server mapfile must be set to DUMP TRUE.

wms_fees

  • WMS TAG Name: Fees (WMS1.1.1, sect. 7.1.4.2)
  • Description: (Optional) Fees information. Use the reserved word “none” if there are no fees.

wms_keywordlist

  • WMS TAG Name: KeywordList (WMS1.1.1, sect. 7.1.4.2)
  • Description: (Optional) A comma-separated list of keywords or keyword phrases to help catalog searching. As of WMS 1.1.0 no controlled vocabulary has been defined.

wms_onlineresource

  • WMS TAG Name: OnlineResource (WMS1.1.1, sect. 6.2.2)
  • Description: (Recommended) The URL that will be used to access this WMS server. This value is used in the GetCapabilities response.
  • See Also: sections “Setup a Mapfile / wms_onlineresource metadata” and “More About the Online Resource URL” above.

wms_resx, wms_resy

  • WMS TAG Name: BoundingBox (WMS1.1.1, sect. 6.5.6)
  • Description: (Optional) Used in the BoundingBox tag to provide info about spatial resolution of the data, values are in map projection units.

wms_service_onlineresource

  • Description: (Optional) Top-level onlineresource URL. MapServer uses the onlineresource metadata (if provided) in the following order:

    1. wms_service_onlineresource
    2. ows_service_onlineresource

    3. wms_onlineresource (or automatically generated URL, see the onlineresource section of this document)

wms_srs

  • WMS TAG Name: SRS (WMS1.1.1, sect. 6.5.5)
  • Description: (Recommended) Contains a list of EPSG projection codes that should be advertized as being available for all layers in this server. The value can contain one or more EPSG:<code> pairs separated by spaces (e.g. “EPSG:4269 EPSG:4326”) This value should be upper case (EPSG:42304.....not epsg:42304) to avoid problems with case sensitive platforms.
  • See Also: section “Setup a Mapfile / Map PROJECTION and wms_srs metadata” above.

wms_timeformat

  • Description: The time format to be used when a request is sent. (e.g. “wms_timeformat” “%Y-%m-%d %H, %Y-%m-%d %H:%M”). Please see the WMS Time Support Howto for more information.

wms_title

  • WMS TAG Name: Title (WMS1.1.1, sect. 7.1.4.1)
  • Description: (Required) A human-readable name for this Layer.

Layer Object Metadata

gml_exclude_items

  • Description: (Optional, applies only to GetFeatureInfo GML requests) A comma delimited list of items to exclude. As of MapServer 4.6, you can control how many attributes (fields) you expose for your data layer with metadata. The previous behaviour was simply to expose all attributes all of the time. The default is to expose no attributes at all. An example excluding a specific field would be:

    "gml_include_items" "all"
    "gml_exclude_items" "Phonenum"
    

gml_groups

  • Description: (Optional, applies only to GetFeatureInfo GML requests) A comma delimited list of group names for the layer.

gml_[group name]_group

  • Description: (Optional, applies only to GetFeatureInfo GML requests) A comma delimited list of attributes in the group. Here is an example:

    "gml_include_items" "all"
    "gml_groups"        "display"
    "gml_display_group" "Name_e,Name_f"
    

gml_include_items

  • Description: (Optional, applies only to GetFeatureInfo GML requests) A comma delimited list of items to include, or keyword “all”. As of MapServer 4.6, you can control how many attributes (fields) you expose for your data layer with this metadata. The previous behaviour was simply to expose all attributes all of the time. You can enable full exposure by using the keyword “all”, such as:

    "gml_include_items" "all"
    

    You can specify a list of attributes (fields) for partial exposure, such as:

    "gml_include_items" "Name,ID"
    

    The new default behaviour is to expose no attributes at all.

gml_[item name]_alias

  • Description: (Optional, applies only to GetFeatureInfo GML requests) An alias for an attribute’s name. The served GML will refer to this attribute by the alias. Here is an example:

    "gml_province_alias" "prov"
    

gml_[item name]_type

  • Description: (Optional, applies only to GetFeatureInfo GML requests) Specifies the type of the attribute. Valid values are Integer|Real|Character|Date|Boolean.

gml_xml_items

  • Description: (Optional, applies only to GetFeatureInfo GML requests) A comma delimited list of items that should not be XML-encoded.

wms_abstract

  • Same as wms_abstract in the Web Object.

wms_attribution_logourl_format

  • Description: (Optional) The MIME type of the logo image. (e.g. “image/png”). Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_height

  • Description: (Optional) Height of the logo image in pixels. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_href

  • Description: (Optional) URL of the logo image. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_logourl_width

  • Description: (Optional) Width of the logo image in pixels. Note that the other wms_attribution_logourl_* metadata must also be specified.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_onlineresource

  • Description: (Optional) The data provider’s URL.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_attribution_title

  • Description: (Optional) Human-readable string naming the data provider.
  • refer to section 7.1.4.5.11 of the WMS 1.1.1 spec.

wms_dataurl_format

  • Description: (Optional) Non-standardized file format of the metadata. The layer metadata wms_dataurl_href must also be specified.
  • refer to section 7.1.4.5.14 of the WMS 1.1.1 spec.

wms_dataurl_href

  • Description: (Optional) The URL to the layer’s metadata. The layer metadata wms_dataurl_format must also be specified.
  • refer to section 7.1.4.5.14 of the WMS 1.1.1 spec.

wms_extent

  • WMS TAG Name: BoundingBox (WMS1.1.1, sect. 6.5.6)

  • Description: (Optional) Used for the layer’s BoundingBox tag for cases where it is impossible (or very inefficient) for MapServer to probe the data source to figure its extents. The value for this metadata is “minx miny maxx maxy” separated by spaces, with the values in the layer’s projection units. If wms_extent is provided then it has priority and MapServer will NOT try to read the source file’s extents.

    For Rasters served through WMS, MapServer can now use the wms_extent metadata parameter to register the image. If a .wld file cannot be found, MapServer will then look for the wms_extent metadata parameter and use the extents of the image and the size of the image for georegistration.

wms_group_abstract

  • Description: (Optional) A blurb of text providing more information about the group. Only one layer for the group needs to contain wms_group_abstract, MapServer will find and use the value. The value found for the first layer in the group is used. So if multiple layers have wms_group_abstract set then only the first value is used.

wms_group_title

  • WMS TAG Name: Group_title (WMS1.1.1, sect. 7.1.4.1)
  • Description: (Optional) A human-readable name for the group that this layer belongs to. Only one layer for the group needs to contain wms_group_title, MapServer will find and use the value. The value found for the first layer in the group is used. So if multiple layers have wms_group_title set then only the first value is used.

wms_keywordlist

  • Same as wms_keywordlist in the Web Object .

wms_layer_group

  • Description: (Optional) Can be used to assign a layer to a number of hierarchically nested groups. This grouped hierarchy will be expressed in the capabilities.

    WMS_LAYER_GROUP is different from the GROUP keyword in that it does not publish the name of the group in the capabilities, only the title. As a consequence the groups set with WMS_LAYER_GROUP can not be requested with a GetMap or GetFeatureInfo request (see section 7.1.4.5.2 of the WMS implementation specification version 1.1.1. (OGC 01-068r2)). Another difference is that GROUP does not support nested groups. The purpose of this metadata setting is to enable making a WMS client aware of layer grouping.

    All group names should be preceded by a forward slash (/). It is not allowed to use both the WMS_LAYER_GROUP setting and the GROUP keyword for a single layer.

    LAYER
      NAME "mylayer"
      DATA "mylayer"
      TYPE LINE
      CLASS
        STYLE
          COLOR 100 100 255
        END
      END
      METADATA
       "WMS_LAYER_GROUP" "/rootgroup/subgroup"
      END
    END
    

wms_metadataurl_format

  • Description: (Optional) The file format MIME type of the metadata record (e.g. “text/plain”). The layer metadata wms_metadataurl_type and wms_metadataurl_href must also be specified.
  • refer to section 7.1.4.5.10 of the WMS 1.1.1 spec.

wms_metadataurl_href

  • Description: (Optional) The URL to the layer’s metadata. The layer metadata wms_metadataurl_format and wms_metadataurl_type must also be specified.
  • refer to section 7.1.4.5.10 of the WMS 1.1.1 spec.

wms_metadataurl_type

  • Description: (Optional) The standard to which the metadata complies. Currently only two types are valid: “TC211” which refers to [ISO 19115], and “FGDC” which refers to [FGDC-STD-001-1988]. The layer metadata wms_metadataurl_format and wms_metadataurl_href must also be specified.
  • refer to section 7.1.4.5.10 of the WMS 1.1.1 spec.

wms_opaque

  • WMS TAG Name: Opaque (WMS1.1.1, sect. 7.1.4.6.3)
  • Description: (Optional) Set this metadata to “1” to indicate that the layer represents an area-filling coverage of space (e.g. a bathymetry and elevation layer). This should be taken by the client as a hint that this layer should be placed at the bottom of the stack of layers.

wms_srs

  • Same as wms_srs in the Web Object .

wms_style

  • Description: (Optional) The LegendURL style name. Requires the following metadata: wms_style_<style’s_name>_width, wms_style_<style’s_name>_legendurl_height, wms_style_<style’s_name>_legendurl_format, wms_style_<style’s_name>_legendurl_href
  • refer to section 7.1.4.5.4 of the WMS 1.1.1 spec.

wms_style_<style’s_name>_legendurl_height

  • Description: (Optional) The height of the legend image in pixels. Requires the following metadata: wms_style_<style’s_name>_width, wms_style, wms_style_<style’s_name>_legendurl_format, wms_style_<style’s_name>_legendurl_href.
  • refer to section 7.1.4.5.4 of the WMS 1.1.1 spec.

wms_style_<style’s_name>_legendurl_href

  • Description: (Optional) The URL to the layer’s legend. Requires the following metadata: wms_style_<style’s_name>_width, wms_style_<style’s_name>_legendurl_height, wms_style_<style’s_name>_legendurl_format, wms_style.
  • refer to section 7.1.4.5.4 of the WMS 1.1.1 spec.

wms_style_<style’s_name>_legendurl_format

  • Description: (Optional) The file format MIME type of the legend image. Requires the following metadata: wms_style_<style’s_name>_width, wms_style_<style’s_name>_legendurl_height, wms_style, wms_style_<style’s_name>_legendurl_href.
  • refer to section 7.1.4.5.4 of the WMS 1.1.1 spec.

wms_style_<style’s_name>_legendurl_width

  • Description: (Optional) The width of the legend image in pixels. Requires the following metadata: wms_style_<style’s_name>_format, wms_style_<style’s_name>_legendurl_height, wms_style, wms_style_<style’s_name>_legendurl_href.
  • refer to section 7.1.4.5.4 of the WMS 1.1.1 spec.

wms_timedefault

  • Description: (Optional for Time Support) This value is used if it is defined and the Time value is missing in the request. Please see the WMS Time Support Howto for more information.

wms_timeextent

  • Description: (Mandatory for Time Support) This is used in the capabilities to return the valid time values for the layer. The value defined here should be a valid time range. Please see the WMS Time Support Howto for more information.

wms_timeitem

  • Description: (Mandatory for Time Support) This is the name of the field in the DB that contains the time values. Please see the WMS Time Support Howto for more information.

wms_title

  • Same as wms_title in the Web Object.

Sample WMS Server Mapfile

The following is a very basic WMS Server mapfile:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
NAME "WMS-test"
STATUS ON
SIZE 400 300
SYMBOLSET ../etc/symbols.sym
EXTENT -2200000 -712631 3072800 3840000
UNITS METERS
SHAPEPATH "../data"
IMAGECOLOR 255 255 255
FONTSET ../etc/fonts.txt

WEB
  IMAGEPATH "/ms4w/tmp/ms_tmp/"
  IMAGEURL "/ms_tmp/"
  METADATA
    "wms_title"     "WMS Demo Server"  ##required
    "wms_onlineresource" "http://yourpath/cgi-bin/mapserv.exe?"   ##required
    "wms_srs"       "EPSG:42304 EPSG:42101 EPSG:4269 EPSG:4326"  ##recommended
  END
END

PROJECTION
  "init=epsg:42304"   ##required
END

#
# Start of layer definitions
#

LAYER
  NAME "park"
  METADATA
    "wms_title"    "Parks"   ##required
  END
  TYPE POLYGON
  STATUS OFF
  DATA park
  PROJECTION
    "init=epsg:42304"   ##recommended
  END
  CLASS
    NAME "Parks"
    STYLE
      COLOR 200 255 0
      OUTLINECOLOR 120 120 120
    END
  END
END # Layer

LAYER
  NAME popplace
  METADATA
    "wms_title"    "Cities"  ##required
  END
  TYPE POINT
  STATUS ON
  DATA popplace
  PROJECTION
    "init=epsg:42304"   ##recommended
  END
  CLASS
    NAME "Cities"
    STYLE
      SYMBOL 2
      SIZE 8
      COLOR 0 0 0
    END
  END
END # Layer

END # Map File

FAQ / Common Problems

Q:

How can I find the EPSG code for my data’s projection?

A:

If you know the parameters of your data’s projection, then you can browse the “epsg” file that comes with PROJ4 and look for a projection definition that matches your data’s projection. It’s a simple text file and the EPSG code is inside brackets (<...>) at the beginning of every line.

The “epsg” file is usually located in /usr/local/share/proj/ on Unix systems and in C:/PROJ/ or C:/PROJ/NAD in Windows systems (depending on the installation). MS4W users will find the epsg file in /MS4W/proj/nad/.


Q:

My WMS server produces the error “msProcessProjection(): no system list, errno: ..”

A:

That’s likely PROJ4 complaining that it cannot find the “epsg” projection definition file. Make sure you have installed PROJ 4.4.3 or more recent and that the “epsg” file is installed at the right location. On Unix it should be under /usr/local/share/proj/, and on Windows PROJ looks for it under C:/PROJ/ or C:/PROJ/NAD (depending on the installation). You should also check the error documentation to see if your exact error is discussed.

If you don’t have the “epsg” file then you can get it as part of the PROJ4 distribution at http://www.remotesensing.org/proj/ or you can download it at http://www.maptools.org/dl/proj4-epsg.zip.


Q:

How do AUTO projections work?

A:

When a WMS client calls a WMS server with an auto projection, it has to specify the SRS in the form: AUTO: proj_id,unit_id,lon0,lat0 where:

  • proj_id is one of 42001, 42002, 42003, 42004, or 42005 (only five auto projections are currently defined).
  • unit_id is always 9001 for meters. (It is uncertain whether anyone supports any other units.)
  • lon0 and lat0 are the coordinates to use as the origin for the projection.

When using an AUTO projection in WMS GetCapabilities, you include only the “AUTO:42003” string in your wms_srs metadata, you do not include the projection parameters. Those are added by the application (client) at runtime depending on the map view. For example:

NAME "DEMO"
...

WEB
...
METADATA
   "wms_title"            "WMS Demo Server"
   "wms_onlineresource"   "http://my.host.com/cgi-bin/mapserv?map=wms.map&"
   "wms_srs"              "AUTO:42001 AUTO:42002"
END
END

The above server advertises the first two auto projections.