"Failed to load json data" error

Timeline (module for Omeka S)

New versions of this module and support for Omeka S version 3.0 and above are available on GitLab, which seems to respect users and privacy better than the previous repository.

Timeline is a module for Omeka S that integrates the SIMILE Timeline widget and the online Knightlab timeline to create timelines.

Installation

Uncompress files in the module directory and rename module folder Timeline.

Then install it like any other Omeka module and follow the config instructions.

Note: If Omeka is https, if external assets are used, and if the Simile library is used, the library will not load on recent browsers, because the online library contains an url with unsecure http. In that case, you need to set the option "Use Internal library for Simile".

Usage

Once enabled, the module adds two new block for site pages. The first allows to create an automatic timeline, the other one an exhibit with selected items. Simply select one of them and config it (the item pool and eventually the options). Furthermore, any timeline can be created dynamically via /api/timeline.

Fields

Choose which fields you want the module to use on the timeline by default.

Item Title: The field you would like displayed for the item’s title in its information bubble. The default is dcterms:title.
Item Description: The field you would like displayed for the item’s description in its information bubble. The default is dcterms:description.
Item Date: The field you would like to use for item dates on the timeline. The default is dcterms:date.
Item Date End: The field you would like to use for item end dates on the timeline. It is useless if dates are ranges (see below) or if you don’t have end date.
Render Year: Date entered as a single number, like 1066, can be skipped, plotted as a single event or marked as a full year.
Center Date: The date that is displayed by the viewer when loaded. It can be any date with the format YYYY-MM-DD. An empty string means now, a 0000-00-00 the earliest date and 9999-99-99 the latest date.
Viewer: The raw json parameters for the viewer, for example to display only one row, or to change the scale.

All these parameters can be customized for each timeline.

Url for the dynamic json

The json is available at "/api/timeline?block-id=xxx". This url supports any dynamic standard item query too if you want to get the json without a block. The old "/timeline" is deprecated and will be removed in a future version.

By default, the timeline is formatted for Simile. To get the Knightlab format, append ?output=knightlab to the query.

Add a Timeline Block or an Timeline Exhibit

Creating a timeline is a two-step process:

From the admin panel, edit a page, then click the "Timeline" button in the list of new blocks to add.
To choose which items appear on your timeline, fill the "Item Pool" form. The options are the same than in the config by default (see above).

Ready! Open the page.

Important: The number of items should be limited according to the memory of the server: currently, the json output is created in one shot, so it can't manage more than some dozens or hundreds of items.

Dates for Items

Timeline will attempt to convert the value for a date string into an ISO 8601 date format. Some example date values you can use:

January 1, 2012
2012-01-01
1 Jan 2012
2012-12-15

To denote spans of time, separate the start and end date with a /:

January 1, 2012/February 1, 2012

A common format is managed too:

1939-1945

It must be 1939/1945 to be compatible with the standard ISO 8601.

Timeline handles dates with years shorter than 4 digits. For these you may need to pad the years with enough zeros to make them have four digits. For example, 476 should be written 0476.

Also, you can enter in years before common era by putting a negative sign before the year. If the date has less than four digits, you’ll also need to add extra zeros.

So here are some more examples of dates.

0200-01-01
0002-01-01
-0002-01-01
-2013-01-01

When a date is a single number, like 1066, a parameter in the config page allows to choose its rendering:

skip the record (default)
1st January
1st July
full year (range period)

This parameter applies with a range of dates too, for example 1939/1945.

In all cases, it’s recommended to follow the standard ISO 8601 as much as possible and to be as specific as possible.

Parameters of the viewer

Some parameters of the viewer may be customized for each timeline.

Simile timeline

Currently, only the CenterDate and the bandInfos are managed for the Simile timeline. The default is automatically included when the field is empty.

{
    "bandInfos": [
        {
            "width": "80%",
            "intervalUnit": Timeline.DateTime.MONTH,
            "intervalPixels": 100,
            "zoomIndex": 10,
            "zoomSteps": new Array(
                {"pixelsPerInterval": 280, "unit": Timeline.DateTime.HOUR},
                {"pixelsPerInterval": 140, "unit": Timeline.DateTime.HOUR},
                {"pixelsPerInterval": 70, "unit": Timeline.DateTime.HOUR},
                {"pixelsPerInterval": 35, "unit": Timeline.DateTime.HOUR},
                {"pixelsPerInterval": 400, "unit": Timeline.DateTime.DAY},
                {"pixelsPerInterval": 200, "unit": Timeline.DateTime.DAY},
                {"pixelsPerInterval": 100, "unit": Timeline.DateTime.DAY},
                {"pixelsPerInterval": 50, "unit": Timeline.DateTime.DAY},
                {"pixelsPerInterval": 400, "unit": Timeline.DateTime.MONTH},
                {"pixelsPerInterval": 200, "unit": Timeline.DateTime.MONTH},
                {"pixelsPerInterval": 100, "unit": Timeline.DateTime.MONTH} // DEFAULT zoomIndex
            )
        },
        {
            "overview": true,
            "width": "20%",
            "intervalUnit": Timeline.DateTime.YEAR,
            "intervalPixels": 200
        }
    ]
}

Knightlab timeline

You can find all the available parameters in the Knightlab timeline documentation.

Notes:

When a field is not filled, the properties of the resource are used (title, description, creator).
Date should be ISO-8601, partial ("YYYY", etc.) or full ("YYYY-MM-DDT00:00:00Z"). Let blank to use the date of the attachment.
The main display date override start and end dates in some places.
The resource can be an item id, a media id, or any other resource id.
If the resource is not set, it’s possible to use an external content, generally an url, but the viewer supports some other content.
Events are automatically sorted.

Modifying the block template for Timeline

To modify the block template, copy it in your theme (file view/common/block-layout/timeline.phtml).

Modifying the viewer

The template file used to load the timeline is asset/js/timeline.js.

You can copy it in your themes/my_theme/asset/js folder to customize it. The same for the default css. See the main wiki, an example of use with Neatline for Omeka Classic, and the examples of customization on the wiki.

TODO

Integrate attachments for the exhibit and improve the form (hide all by default except resource),
Integrate Numeric data type Interval and Duration (?).
Create the json for knightlab directly from the controller, not the js in view.

Warning

Use it at your own risk.

It’s always recommended to backup your files and your databases and to check your archives regularly so you can roll back if needed.

Troubleshooting

See online issues on the module issues page on GitLab.

License

This module is published under the CeCILL v2.1 license, compatible with GNU/GPL and approved by FSF and OSI.

This software is governed by the CeCILL license under French law and abiding by the rules of distribution of free software. You can use, modify and/ or redistribute the software under the terms of the CeCILL license as circulated by CEA, CNRS and INRIA at the following URL "http://www.cecill.info".

As a counterpart to the access to the source code and rights to copy, modify and redistribute granted by the license, users are provided only with a limited warranty and the software's author, the holder of the economic rights, and the successive licensors have only limited liability.

In this respect, the user's attention is drawn to the risks associated with loading, using, modifying and/or developing or reproducing the software by the user in light of its specific status of free software, that may mean that it is complicated to manipulate, and that also therefore means that it is reserved for developers and experienced professionals having in-depth computer knowledge. Users are therefore encouraged to load and test the software's suitability as regards their requirements in conditions enabling the security of their systems and/or data to be ensured and, more generally, to use and operate it in the same conditions as regards security.

The fact that you are presently reading this means that you have had knowledge of the CeCILL license and that you accept its terms.

The module uses the widget SIMILE Timeline, published under the license MIT. See files in asset/vendor for more info.

Copyright

Module

Copyright The Board and Visitors of the University of Virginia, 2010–2012

Translations

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

This Omeka S module is a full rewrite of the fork of NeatlineTime plugin for Omeka Classic. The original NeatlineTime plugin was created by the Scholars’ Lab at the University of Virginia Library and improved by various authors.