Image

Image

For API information, see the Image Layer API Docs.

Google

Google

Layer for using Google Maps data within OpenLayers. For API information, see the Google Layer API Docs. For an example of usage, see the Spherical Mercator example.
If you are overlaying other data on a Google Maps base layer, you will want to be interacting with the Google Maps layer in projected coordinates. (This is important if you are working with imagery data especially.) You can read more about the ‘Spherical Mercator’ projection that Google Maps – and other commercial layers – use in the Spherical Mercator documentation.
The Google Layer class is designed to be used only as a base layer.

Raster Layers

Raster Layers

Raster Layers are imagery layers. These layers are typically in a fixed projection which can not be changed on the client side.

Non Base Layers

Non Base Layers

Non base layers – sometimes called overlays – are the alternative to Base Layers. Multiple non-base layer can be enabled at a time. These layers do not control the zoom levels of the map, but can be enabled or disabled at certain scales by min/max scale/resolution parameters so that they are only enabled at a certain level.
Some types of overlays support reprojection to the base layer projection at layer load time. Most overlay layers default to non-base overlays, as does the base Layer class. Non-base Layers always display above base layers.

Base Layers

Base Layers

Base Layers are mutually exclusive layers, meaning only one can be enabled at any given time. The currently active base layer determines the available projection (coordinate system) and zoom levels available on the map.
Whether a layer is a base layer or not is determined by the isBaseLayer property on the layer. Most raster layers have the isBaseLayer property set to true by default. It can be changed in the layer options.
Base Layers always display below overlay layers.

Base Layers and Non-Base Layers

Base Layers and Non-Base Layers

OpenLayers has two types of layers when operating in your application: base layers and overlays. This difference controls several aspects of how you interact with an OpenLayers Map.

LayersLayers

Layers

Layers are the ‘datasources’ in OpenLayers.

Layer Constructor

The next step to creating a viewer is to add a layer to the Map. OpenLayers supports many different data sources, from WMS to Yahoo! Maps to WorldWind. In this example, the WMS layer is used. The WMS layer is an example provided by MetaCarta.

var wms = new OpenLayers.Layer.WMS(
  "OpenLayers WMS",
  "http://labs.metacarta.com/wms/vmap0",
  {'layers':'basic'} );
map.addLayer(wms);

Map Constructor

in order to create the viewer, you must first create a map. The OpenLayers.Map constructor requires one argument: This argument must either be an HTML Element, or the ID of an HTML element. This is the element in which the map will be placed.

var map = new OpenLayers.Map('map');

Creating the Map Viewer

In order to create the viewer, you must first create a map. The OpenLayers.Map constructor requires one argument: This argument must either be an HTML Element, or the ID of an HTML element. This is the element in which the map will be placed.

var map = new OpenLayers.Map('map');

Ex. 2: Map Constructor
The next step to creating a viewer is to add a layer to the Map. OpenLayers supports many different data sources, from WMS to Yahoo! Maps to WorldWind. In this example, the WMS layer is used. The WMS layer is an example provided by MetaCarta.

var wms = new OpenLayers.Layer.WMS(
  "OpenLayers WMS",
  "http://labs.metacarta.com/wms/vmap0",
  {'layers':'basic'} );
map.addLayer(wms);

Ex. 3: Layer Constructor
The first parameter in this constructor is the URL of the WMS server. The second argument is an object containing the parameterss to be appended to the WMS request.
Finally, in order to display the map, you must set a center and zoom level. In order to zoom to fit the map into the window, you can use the zoomToMaxExtent function, which will zoom as close as possible while still fitting the full extents within the window.

OpenLayers. Layer.WMS | Constructor

Create a new WMS layer object

Example

var wms = new OpenLayers.Layer.WMS("NASA Global Mosaic",
                                   "http://wms.jpl.nasa.gov/wms.cgi",
                                   {layers: "modis,global_mosaic"});

Parameters

name	{String} A name for the layer
url	{String} Base url for the WMS (e.g.  http://wms.jpl.nasa.gov/wms.cgi)
params	{Object} An object with key/value pairs representing the GetMap query string parameters and parameter values.
options	{Ojbect} Hashtable of extra options to tag onto the layer

Creating Your First Map

The OpenLayers API has two concepts which are important to understand in order to build your first map: ‘Map’, and ‘Layer’. An OpenLayers Map stores information about the default projection, extents, units, and so on of the map. Inside the map, data is displayed via ‘Layer’s. A Layer is a data source – information about how OpenLayers should request data and display it.

Openlayers Tutorials

OpenLayers makes it easy to put a dynamic map in any web page. It can display map tiles and markers loaded from any source. MetaCarta developed the initial version of OpenLayers and gave it to the public to further the use of geographic information of all kinds. OpenLayers is completely free, Open Source JavaScript, released under a BSD-style License.

Installing Openlayers in Ubuntu

With this post I will show hot to install MapServer 4.10.3 in Ubuntu 7.10 (but this procedure should work also for previous Ubuntu versions) from repositories.
1) set Ubuntu sources needed for this software
Add universe ( http://archive.ubuntu.com/gutsy/universe ) and multiverse repositories to your sources (by default are not in Ubuntu)

sudo gedit /etc/apt/sources.list

and uncomment this two lines:

deb http://archive.ubuntu.com/ubuntu/ gutsy-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ gutsy-security main restricted universe multiverse

save the sources.list file and then then update your sources:

sudo apt-get update

2) Install MapServer
now download and install MapServer:

sudo apt-get install cgi-mapserver mapserver-bin mapserver-doc php5-mapscript python-mapscript

MapServer 4.10.3 will be installed (latest of MapServer 4.x serie, the actual MapServer is at 5.0.0), as indicated by typing:

/usr/lib/cgi-bin/mapserv -v
MapServer version 4.10.3 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=THREADS SUPPORTS=GEOS INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG

This is where packages have been installed:

• mapserv is installed from cgi-mapserver package in /usr/lib/cgi-bin
• command line utilities (like shp2img) are installed by the mapserver-bin package in /usr/bin
• some documentations is installed by the mapserver-cod package in /usr/share/doc/mapserver-doc

Test mapserv for cgi by typing (it should work as far you have left the default web site in Apache 2.2): http://localhost/cgi-bin/mapserv
3) Download MapServer Demo
Download the Mapserver 4.x Demo Application from the MapServer web site: http://maps.dnr.state.mn.us/mapserver_demos/workshop.zip
extract the zip file wherever you like, for example i have extracted it here: /home/corti/public_html/mapserverdemo
4) Configure Apache httpd
Configure an httpd virtual host for MapServer. For example we will create a mapserverdemo virtual host editing the default file

sudo gedit /etc/apache2/sites-available/default

this is how I created this virtual host (you may need to change path according to where you have extracted the demo zip file):

 *:80>
 ServerName mapserverdemo
 DocumentRoot /home/corti/public_html/mapserverdemo
 
  />
  Options FollowSymLinks
  AllowOverride All
 >
 
 ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
  "/usr/lib/cgi-bin">
  AllowOverride None
  Options ExecCGI -MultiViews +SymLinksIfOwnerMatch
  Order allow,deny
  Allow from all
 >
 
 ErrorLog /var/log/apache2/mapserverdemo_error.log.
 LogLevel warn
 CustomLog /var/log/apache2/mapserver_access.log combined
 ServerSignature On
>

now let’s add a mapserverdemo host:

sudo gedit /etc/hosts

and add this line:
127.0.0.1 mapserverdemo
save the file and restart Apache:

sudo /etc/init.d/apache2 restart

create a tmp directory in your mapserverdemo root, with writing permissions for the Apache user
Now if you go to http://mapserverdemo/workshop/ you will see a form, but after that it will not work as far we need to add the html form settings to our settings.
If you go at: http://mapserverdemo/cgi-bin/mapserv you should get this response:

No query information to decode. QUERY_STRING is set, but empty.

5) Configure the MapServerDemo
Now let’s configure the demo with our settings.
Edit this section in index.html file (wherever you have extracted the demo), according to your settings:

    <form name="demo" method="GET" action="/cgi-bin/mapserv" onSubmit="submit_form()">
 
   .......
 
      
      <input type="hidden" name="map" value="/home/corti/public_html/mapserverdemo/workshop/itasca.map">
      <input type="hidden" name="program" value="/cgi-bin/mapserv">
      <input type="hidden" name="root" value="/mapserver_demos/workshop">
      <input type="hidden" name="map_web_imagepath" value="/home/corti/public_html/mapserverdemo/tmp/">
      <input type="hidden" name="map_web_imageurl" value="/tmp/">

go to: http://mapserverdemo/workshop/ and the demo should work. Enjoy!

Installing Mapserver -Windows

We just need to setup MapServer to run on a local machine for now and the best way to do that is to use MapServer for Windows (MS4W). This package is a all-in-one web mapping environment. It comes complete with Apache Web Server, PHP, MapServer, and other open source GIS utilities. Here’s how to set it up and add a “Google Maps”-like interface (using ka-Map) in under 10 minutes . I won’t describe the details of how everything interacts because you don’t really have to know right now. It just works.

1. Download the MS4W PHP5 Base Installer v2.2.6 (Sept 18,2007) from here.
2. Unzip the file to the root of your C:\ drive and this will create a folder C:\ms4w.
3. For some initial data, download the PHP/MapScript Sample Application here. The zip file is named gmap_ms4w_ms410.zip.
4. Again, unzip this file at the root of your C:\ drive and it will automatically be placed into the folder C:\ms4w\apps\gmap.
5. Download the ka-Map Javascript API from the same page. This file is named ka-map-ms4w-1.0.zip.
6. Again, unzip this file to the root of your C:\ drive and it will automatically be placed into the folder C:\ms4w\apps\ka-map-1.0.
7. Navigate to C:\ms4w and double-click on the file named apache-install.bat. In one-click, you’ve setup your web server and MapServer is ready to use.
8. Open your web browser and goto http://localhost/. You should see an Introduction to MapServer 4 Windows page.
9. Scroll to the bottom of the page and click the ka-Map Sample Interface link. This will load up the sample application we downloaded in step 3 using the ka-Map interface. The map should look like this:

Congratulations! You’ve just setup a mapping website. In short, ka-Map is basically a web page front-end for MapServer that is similar to Google Maps. MapServer is used to generate map images in the form of map tiles and ka-Map then presents them to the user so they can pan, zoom, identify, and search the map. More details to follow in later posts.

Introduction to MapServer

One of the most popular open source GIS applications is MapServer. Initially developed by the University of Minnesota, MapServer has evolved into a fast and easy-to-use internet map server.

“MapServer is an Open Source development environment for building spatially-enabled internet applications. MapServer is not a full-featured GIS system, nor does it aspire to be. Instead, MapServer excels at rendering spatial data (maps, images, and vector data) for the web.” – http://mapserver.gis.umn.edu/

Integrating Map Inside Map Using OpenLayers

http://yadadrop.com/drupal-video/openlayers-tutorial-drupal-map-integration

http://www.drupalove.com/drupal-video/openlayers-and-drupal-integration