Carry out the following steps:
- We will first create a WMS for the PostGIS hotspot layer. Create a mapfile named hotspots.map in a directory accessible to the HTTPD (or IIS) user (for example, /var/www/data in Linux, /Library/WebServer/Documents/ for macOS, and C:\ms4w\Apache\htdocs in Windows), by executing the following code after adjusting the database connection settings:
MAP # Start of mapfile
NAME 'hotspots_time_series'
IMAGETYPE PNG
EXTENT -180 -90 180 90
SIZE 800 400
IMAGECOLOR 255 255 255
# map projection definition
PROJECTION
'init=epsg:4326'
END
# a symbol for hotspots
SYMBOL
NAME "circle"
TYPE ellipse
FILLED true
POINTS
1 1
END
END
# web section: here we define the ows services
WEB
# WMS and WFS server settings
METADATA
'wms_name' 'Hotspots'
'wms_title' 'World hotspots time
series'
'wms_abstract' 'Active fire data detected
by NASA Earth Observing
System Data and Information
System (EOSDIS)'
'wms_onlineresource' 'http://localhost/cgi-bin/
mapserv?map=/var/www/data/
hotspots.map&'
'wms_srs' 'EPSG:4326 EPSG:3857'
'wms_enable_request' '*'
'wms_feature_info_mime_type' 'text/html'
END
END
# Start of layers definition
LAYER # Hotspots point layer begins here
NAME hotspots
CONNECTIONTYPE POSTGIS
CONNECTION 'host=localhost dbname=postgis_cookbook
user=me
password=mypassword port=5432'
DATA 'the_geom from chp09.hotspots'
TEMPLATE 'template.html'
METADATA
'wms_title' 'World hotspots time
series'
'gml_include_items' 'all'
END
STATUS ON
TYPE POINT
CLASS
SYMBOL 'circle'
SIZE 4
COLOR 255 0 0
END # end of class
END # hotspots layer ends here
END # End of mapfile
- Check whether the WMS GetCapabilities request for this mapfile is working well by typing the following URLs in the browser:
- http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map&SERVICE=WMS&VERSION=1.0.0&REQUEST=GetCapabilities (in Linux)
- http://localhost/cgi-bin/mapserv.exe?map=C:\ms4w\Apache\htdoc\shotspots.map&SERVICE=WMS&VERSION=1.0.0&REQUEST=GetCapabilities (in Windows)
- http://localhost/cgi-bin/mapserv?map=/Library/WebServer/Documents/hotspots.map& SERVICE=WMS&VERSION=1.0.0&REQUEST=GetCapabilities (in macOS)
In the following steps, we will be referring to Linux. If you are using Windows, you just need to replace http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map with http://localhost/cgi-bin/mapserv.exe?map=C:\ms4w\Apache\htdoc\shotspots.map; or if using macOS, replace it with http://localhost/cgi-bin/mapserv?map=/Library/WebServer/Documents/hotsposts.map in every request:
- Now query the WMS service with a GetMap request. Type the following URL in the browser. If everything is correct, MapServer should return an image with some hotspots as a response. The URL is http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map&&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=-25,-100,35,-35&CRS=EPSG:4326&WIDTH=1000&HEIGHT=800&LAYERS=hotspots&STYLES=&FORMAT=image/png.
The map displayed on your browser will look as follows:
- Until now, you have implemented a simple WMS service. Now, to make the TIME parameter available for WMS Time requests, add the wms_timeextent, wms_timeitem and wms_timedefault variables in the LAYER METADATA section, as follows:
METADATA
'wms_title' 'World hotspots time
series'
'gml_include_items' 'all'
'wms_timeextent' '2000-01-01/2020-12-31' # time extent
for which the service will give a response
'wms_timeitem' 'acq_date' # layer field to use to filter
on the TIME parameter
'wms_timedefault' '2013-05-30' # default parameter if not
added to the request
END
- Having added these parameters in the LAYER METADATA mapfile section, the WMS GetCapabilities response should change. Now, the hotspots layer definition includes the time dimension, defined by the <Dimension> and <Extent> elements. You will get a response, as follows:
- You can finally test the WMS service with time support. You only need to remember to add the TIME parameter in the GetMap request (otherwise, GetMap will filter out the data using the default date, which is 2017-12-12 in this example) using the URL http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map&&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=-25,-100,35,-35&CRS=EPSG:4326&WIDTH=1000&HEIGHT=800&LAYERS=hotspots&STYLES=&FORMAT=image/png&TIME=2017-12-10.
- Play for a while with the TIME parameter in the preceding URL and try to see how the GetMap image response changes day by day. Remember that, for the dataset we imported, the acq_date range is from 2017-12-07 to 2017-12-14; but in your case, if you didn't use the hostpots shapefile included in the book dataset, the time range will be different!
The following are different outputs for the mentioned dates and the full URLs used to query the service:- http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map&&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=-25,-100,35,-35&CRS=EPSG:4326&WIDTH=1000&HEIGHT=800&LAYERS=hotspots&STYLES=&FORMAT=image/png&TIME=2017-12-14. The output is as follows (2017-12-14):
-
- http://localhost/cgi-bin/mapserv?map=/var/www/data/hotspots.map&&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=-25,-100,35,-35&CRS=EPSG:4326&WIDTH=1000&HEIGHT=800&LAYERS=hotspots&STYLES=&FORMAT=image/png&TIME=2017-12-07. The output is as follows (2017-12-07):
