Working with geospatial data can be difficult. The NeatlineMaps plugin allows you to upload georeferenced maps to the popular open source Geoserver, allowing you not only to use your data easily in Omeka, but also to share it with others.

GeoServer is a Java-based software server that implements the open standards developed by the Open Geospatial Consortium (OGC). GeoServer works with many of the popular mapping applications like Google Maps, Google Earth, Yahoo Maps, and Microsoft Virtual Earth, as well as with more traditional GIS architectures like ESRI ArcGIS. And now it also integrates with Omeka through the NeatlineMaps plugin.

NeatlineMaps allows you to connect to one or more GeoServer instances to easily create “slippy” maps that you can use with Omeka items and exhibits.

Note: You must have access to a GeoServer instance to use this plugin. You can download the appropriate installation package from the GeoServer site. And read how to install and configure it. NeatlineMaps also requires that the PHP Zip and Curl modules be installed on your server, and it will notify you if you are missing these modules.

Once all dependencies are in place, follow the same process for installing any other Omeka plugin.

• Upload the ‘NeatlineMaps’ plugin directory to your Omeka installation’s ‘plugins’ directory. See Installing a Plugin.
• Activate the plugin from the admin → Settings → Plugins page.

You can add as many GeoServer instances as you have access to. This is particularly useful in a situation where you have a testing and production environment, or working with colleagues from different institutions with a centralized, shared GeoServer instance.

1. Log on to the Omeka Admin panel
2. Click on the Neatline Maps tab
3. Click on the Create Server link or button
4. Fill out the information to connect to your GeoServer instance. If you have a default installation of GeoServer, the username/password combination is ‘admin/geoserver’. We recommend you change this setting.
   • Name: An internal, non-public identifier for the server.
   • URL: The root URL for the Geoserver instance. This should look something like http://localhost:8080/geoserver.
   • Workspace: The workspace on the server where the new GeoTIFF stores should be created.
   • Username: The Geoserver username.
   • Password: The Geoserver password.
   • Active: Check this box if the new server should be the active server. This can be changed at any time. (See below for more information.)
5. After clicking on the Create button, you will be presented with a list of servers which you have defined and the status of each one (green Online or red Offline).

You may create as many sever records as you wish, but at any given point exactly one of the servers will always be the "active" server. This is the server that Neatline Maps will use to handle new GeoTIFF files that are uploaded as files attachments to items.

If you have more than one server record, you can change the active server by clicking the "Set Active" link in the "Active" column in the Browse Servers view or by editing the server record.

There are two ways to add a map on a Geoserver instance.

1. Link to the map directly by adding a WMS address and a list of layers to include.
2. Upload a GeoTIFF as a file.

To link an item to an existing service:

1. In the Add/Edit view of an item, click on the "Web Map Service" in the vertical stack of tabs on the left.
2. Enter the WMS address of the server and a comma-delimited list of layers in the two fields.
3. Click the "Save Changes" button (or "Add Item," if you're creating a new Item).

If the WMS address and layers point to a valid web map service, the map will be displayed along with the regular metadata on all item-specific views throughout the site.

To use this feature, you must have set up a server to post your GeoTIFF images to (see Adding a Server). You also must have administrative access to a Geoserver instance. Once these are in place, you can upload a GeoTIFF in Omeka as you would any file, and NeatlineMaps will communicate with Geoserver to set up the web map service for you.

1. Create a new Omeka item, filling out pertinant metadata fields;
2. Click on the Files tab;
3. Browse to where you have stored your GeoTIFF; and
4. Click Add/Edit Item.

Neatline Maps will detect that a GeoTIFF file has been uploaded and attempt to send the file to the Geoserver instance that is currently marked as "active" in the list of servers under the "Neatline Maps" tab. If the plugin is able to connect to the server and the .tiff file is a well-formed GeoTIFF, Neatline Maps will create a new coverage store and generate a layer for the store. In your Omeka site, Neatline Maps will automatically fill in the information in the "Web Map Service" tab for the item with the WMS address and layer name of the new GeoTIFF that was just uploaded to the active server.

What if you try to upload a new GeoTIFF to an item that already has existing data in the "Web Map Service" tab? If the existing WMS address on the item matches the WMS address of the currently "active" server, Neatline Maps will upload the file to Geoserver, and it will add the new layer to the existing list of layers specified in the "layers" field in the "Web Map Service" tab. If the WMS address of the active server does not match the WMS address on the item, Neatline Maps will do nothing: the file will not be uploaded to Geoserver and the list of layers in the "Web Map Service" tab will not be changed.

For an excellent introduction to georectifying maps for use with the Neatline Maps plugin, see Creating GIS Dataset from Historic Maps.

Once you have an item or a collection of items with WMS services attached to them — either by uploading new GeoTIFFs or pointing the items to existing services — you can add a map to a Neatline exhibit just by activating the item in the "Map" column in the editor.

In the Neatline editor, find the listing for the item in the items browser panel on the left of the screen (depending on how the items query for the exhibit is configured, you might have to update the query or add tag/collection metadata to the item to make it appear in the list) and click the middle of the three activation checkboxes next to the item (in the "Map" column).

Neatline will automatically render the map on the exhibit. In this way, you can configure any combination of WMS maps in the exhibit by activating or deactivating the Omeka items associated with that exhibit.

Often when developing a site, it's useful to be able to work on a separate server running GeoServer, whether on your laptop or on a staging site. You can easily migrate this information to your production server. GeoServer keeps all configuration and data in its data directory. To find where this is, go into GeoServer and click the Server Status link at the top of the left column. The first item on the status page is the location of the data directory.

Now after you install GeoServer on the final server, you can copy the data directory from the old server onto the new server and have access to your data.

We use an issue tracker for feedback on issues and requested improvements. If you have general questions, you may also post them to the Omeka Forums  or the Omeka Developers Group.

• Martin Liebeskind (German)
• Gillian Price (Spanish)
• Oguljan Reyimbaeva (Russian)
• Katina Rogers (French)