rdeboer's sandbox: Openlayers Center Override

A behavior/plugin for Openlayers maps that allows you to set the center and zoom level of a map via parameters appended to the URL of the page that the map appears on.

There are three ways to specify the center:

1. By appending ?center=LON,LAT to the URL.
2. By appending ?ref-node=ID as a parameter to the URL, whereby ID is the node number of a node that has a Geofield on it; the module will use that node's lon,lat as the center of the map you are displaying. ?ref-node=ID may be generated manually or automatically, for instance via the Node Reference URL Widget. Using the Node Reference URL Widget, you can create links to create nodes with maps that use as their center the location of the node they reference, i.e. their parent.
3. As 2), but by appending the reference node ID as a URL argument: /ID

The zoom level is also taken from the URL, &zoom=Z, where Z is an integer in the range 0..21, subject to what your map supports.
If omitted, the zoom level on the Center Override behavior config tab is used instead.

Examples

If you want to send someone an email with a link to a page containing a map on your site and you want that map correctly positioned and zoomed when the recipient opens the link, you'd use something like this:

    example.com/my-page-with-map?center=144.9,-37.7&zoom=10

If you use a node reference field to create child-to-parent relationship and have installed the Node Reference URL Widget module, it will auto-generate on every parent node, a link to create a child:

    node/add/article?ref-node=123

or equivalently:

    node/add/article/123

If the child node contains an Openlayers map or map widget, then you can center that map based on the Geofield that resides on the parent, using the above link.
You may append a zoom level too:

    node/add/article/123?zoom=14

If not specified, then the zoom level is taken from the behaviour configuration belonging to this module.

Installation and configuration

1. Install and enable like any other module.
2. Visit .../admin/structure/openlayers/maps and press Edit next to map that needs to have its center and/or zoom overridden.
3. Under the Behaviors tab find the fieldset Center Override.
4. Flick it on and enter URL parameter name and Initial zoom level
5. Save.