The Omeka + Neatline project’s goal is to enable scholars, students, and library and museum professionals to create geospatial and temporal visualizations of archival collections using a Neatline toolset within CHNM’s popular, open source Omeka exhibition platform. Neatline, a “contribution to interpretive humanities scholarship in the visual vernacular,” is a project of the UVa Library Scholars’ Lab, originally bolstered by a Start-Up Grant from the Office of Digital Humanities at the National Endowment for the Humanities. Omeka is an award-winning web-publishing platform for the display of cultural heritage and scholarly collections and exhibits, funded by the Institute of Museum and Library Services, Alfred P. Sloan Foundation, Andrew W. Mellon Foundation, and Samuel H. Kress Foundation.

This two-year initiative will allow CHNM and the Scholars’ Lab to expand and regularize a partnership that developed informally between the two centers over the course of the past year. Collaboration has already resulted in improvements to the core functionality of Omeka by CHNM and has led the Scholars’ Lab to produce a number of prototype plugins making Omeka a more attractive and viable option for scholarly partnerships with larger libraries and cultural heritage institutions. These include: improved data import (including EAD, a common archival standard); Solr-powered searching and browsing; and Fedora-based repository services. Further development will improve existing plugins, add preservation workflows, and refine the Neatline toolset for integration and sophisticated editing and scholarly annotation of historical maps, GIS layers, and timelines. Enhancements to Omeka’s core APIs, improved documentation, regular “point” releases, and a new Exhibit Builder will strengthen Omeka’s already large and robust user and developer communities.

Omeka + Neatline is one of six contract awards made by the Library of Congress in a program that aims both to improve the Library’s own content management and content delivery infrastructure and to contribute to collaborative knowledge sharing among broader communities concerned with the sustainability and accessibility of digital content. In July of 2010, the Library of Congress targeted approximately $3,000,000 toward Broad Agency Announcements covering three areas of research interest related to these goals. Technical proposals were openly solicited from expert, multi-disciplinary communities in both academic and commercial settings in three areas: Ingest for Digital Content, Data Modeling of Legislative Information, and Open Source Software for Digital Content Delivery.

In addition to guiding software development work at the Scholars’ Lab and CHNM, project directors Tom Scheinfeldt and Bethany Nowviskie will use the Omeka + Neatline project as an opportunity to document and disseminate a model for open source, developer-level collaborations among library labs and digital humanities centers.

In our work on Neatline, we have made a deliberate choice to start by constraining ourselves to map-sources that are quickly and easily provided through WMS. This leaves out (for now) two popular sources of map imagery; Google Maps and Open Street Map. I’m going to explain why we made that choice, and why, when we do come to make these sources usable with Neatline, we will do so with great care and with an eye to scholarly method.

All two-dimensional maps (as opposed to globes) are projected. That is, the curved three-dimensional surface of the Earth is transformed onto a flat two-dimensional surface. This can be done in an infinite variety of ways, many of which have been mathematically characterized and named by cartographers, for whom they are necessary tools. We must note, however, that no such transform can obtain a perfect representation of a section of the Earth. The mapmaker must choose which qualities to preserve and in what measures. Is it more important to provide an accurate depiction of relative areas or of relative lengths? Is the area around Greenland to be kept in the focus of accuracy, or that around New Zealand?

Each map therefore carries with it from its creation certain choices like these, part of the arguments the map makes about the world by its very construction. We chose WMS on which to start building our tools because, amongst other reasons, it allows for the transmission of projection information as part of its operation. This fact allows us to produce imagery from historical maps (themselves in any number of projections) and maintain the original choices the mapmaker made. Google Maps and Open Street Map are not WMS sources. They can be described as tile caches, huge reservoirs of rendered imagery. As such, they offer their own choices about how the world is to be projected. (Google’s choice has become so closely associated with Google that it is known widely as “the Google projection”.)

Now we come to an important technical distinction; WMS services are able (depending on the capabilities of the specific software in use) to reproject their contents. That is, in response to a specific request for imagery, they can produce the imagery in a projection different from the one in which it was stored. GeoServer, the software we are using for Neatline, has a library of thousands of projections to which users can add more as desired. This allows us to take imagery from a WMS source and lay it under a historical map layer while maintaining the original projection for that of the map as a whole. Tile caches, by and large, do not allow for this. (Google Maps offers its one projection, and Open Street Map offers two.) This means that in order to lay historical map imagery over a layer from one of these sources, we would have to reproject the foreground (historical imagery) overriding the choices of the mapmaker and introducing additional choices of our own about what facets of the geographies at stake are to be preserved and which abandoned.

(Neogeographers will remark that georectifying a digital image introduces similar issues. This is true, but unavoidable for our purposes. We would like to avoid compounding the matter in a way that is subtle and hard to detect.)

We are working out means by which we can provide the undeniable utility of popular tilecaching services in a way that is respectful of the historical context and story of map artifacts. Until we do, we will continue to concentrate on the more flexible and sophisticated apparatus provided by WMS.

The Neatline technical crew is hurtling onwards in our Omeka plugin rampage.

Ethan Gruber is now finishing work on his EAD Importer. This will allow folks to bring an Encoded Archival Description XML finding aid to an Omeka instance and have the documents in that archival description sprout right into the Omeka field as manipulable, annotate-able, curate-able items. We’ve successfully applied it to our two test cases (H.P. Lovecraft and Jedediah Hotchkiss) and are working through other examples.

I have been madly thrashing a geospatially-enabled duo of plugins: Neatline Maps and Neatline Features. Neatline Maps connects the powerful open-source Web GIS engine GeoServer to Omeka. It permits a user to upload georeferenced images and have them immediately available as interactive maps. Neatline Features allows users to use a simple but powerful graphical editor built on the OpenLayers library to attach sophisticated georeferenced shape information to Omeka items. This could include anything from an outline of a building to the path taken by an army brigade through a battle.

Lastly, we’ve participated in CHNM‘s Omeka plugin rush and written a new Timeline plugin to replace an obsolete design. We hope to have it published within a few days.

We’re well on our way to our expected May public release. — Adam

Our new technical plan replaces a large number of components with one: Omeka. Omeka is a software framework for collections-based research and Web-based exhibitions created by historians at George Mason University. It will provide us several of the key technical facilities we require for our work. For example, the suite of simple Web-forms to facilitate the ingestion of EAD documents and historical raster-imagery data that we have undertaken to create are now backed by Omeka, which offers generic forms for similar needs that can be customized to our specific plan. It will take only a few weeks to create them by building on Omeka, whereas it would have taken several months to do “from scratch”. By creating our new software tools as “plugins” to the Omeka machinery, we are taking advantage of many such efficiencies. What is more, we are allowing for our future user-community to use our Neatline software in conjunction with a large and growing suite of other Omeka plugins for such tasks as media playback, sophisticated indexing, inter al. Our software development effort is being partially hosted by the Omeka development group at GMU, which not only eliminates the small overhead we would incur to host it locally, but provides us with visibility in a large a growing community of Omeka users.

We have accomplished several milestones in recent weeks. An Omeka plugin for managing georeferenced historic maps has been created and made public to the Omeka community. It has garnered considerable interest. We have accomplished much of the modeling and basic engineering for another Omeka plugin which will manage geographic features. We are currently working on a third which will accomplish the import of EAD into a Neatline project. This component, in particular,will be useful to many people who have no special interest in maps or geography. It will provide a useful and simple way to open archives onto the Web and create curated exhibitions of archival material. — Adam