Using The Digital Archaeological Record
The resources already uploaded to tDAR are free for you to use and download. We only charge a fee for users that want to upload their own resources into the repository. Our prices are based upon the number of files uploaded. File price is based on a sliding scale—the more files purchased the lower the cost per file. Allotted space is “pooled” meaning that if you buy more than one file, the associated space in MB can be distributed between those files in any way you choose. We accept debit and major credit cards including MasterCard, Visa, and American Express.
To begin using the resources available in tDAR, you will have to become a registered user (see How to Register with tDAR). If you wish to upload your own resources after registering, you will need to purchase space (see How to Purchase Files/Space in tDAR) and set up a Payment Account (see Creating & Managing a Billing Account).
tDAR is designed not only to provide archaeologists all over the world with wider access to archaeological information, but also to preserve that information future use. To ensure the serviceability of files, tDAR stores resources in archival file formats designed to be compatible with future software development and to allow resources to be used long after the computers employed in their creation become obsolete. All document resources are stored in both the original format (in which they were submitted) and in an archival format. The original files are maintained at a bit level. To maintain a high level of usability, a derivative format may also be created to conform with contemporary software requirements. For example, Microsoft Excel files (those with a .xls extension) are maintained as submitted, but are also transformed to ASCII comma-separated value files (.csv) as a preservation format. Digital Antiquity will also migrate those Excel files to future versions (e.g., .xlsx) for dissemination.
Users can upload resources to tDAR either as individual files one at a time or, for resources of the same file/resource type, upload resources en masse via batch uploads.
Rich Archaeological Metadata
Metadata are sometimes summarized as “data about your data.” A report by the National Information Standards Organization describes metadata as “structured information that describes, explains, locates, or otherwise makes it easier to retrieve, use, or manage an information resource” (National Information Standards Organization 2004:3).
Utilizing standard formats including Dublin Core and MODS, Digital Antiquity has developed a rich metadata schema tailored to capture archaeological data — encode spatial, temporal, cultural, material, and other keywords, as well as detailed information regarding authorship, sponsorship, and other sorts of credit that must accompany any use of downloaded data.
tDAR allows users to search for and discover archaeological information. Since tDAR contains a large (and ever-expanding) number of archaeological reports, images, datasets and other information, tDAR’s search functions are designed to let users sort and select stored resources based on specific criteria including:
Search results can be browsed, sorted, bookmarked and organized for later review or research.
tDAR enables archaeologists to share their data with other archaeologists (and publics) around the world. tDAR can be used to enhance journal articles and reports by allowing readers to “dig in” to associated data set(s) too large to be published in hardcopy. In addition to supplementing traditional publications, articles, journals, and even primary data can be published through tDAR, allowing the instant dissemination of archaeological information. Digital Antiquity, along with other organizations, is working on a citation format for online resources and primary data so that archaeologists receive credit for sharing their information. tDAR maintains and delivers full citation information for documents, and detailed semantic meta data for each column of data tables.
Researchers can also use tDAR as an online collaboration tool by embargoing resources for a period of time but allowing user-specified researchers to access the uploaded resources.
tDAR includes special features to help researchers find and utilize archaeological data. Digital Antiquity works with search engines such as Google, Google Scholar, and Bing, as well as integrates tDAR with Zotero and other citation and document management tools. All data downloads are provided with appropriate citation information.
The Data Integration tool allows users to integrate two or more databases or spreadsheets and create massive data sets from many smaller data sets.
Documents include site reports, theses, dissertations, articles, background histories, field notes, CRM project reports and anything that is composed mostly of written prose.
Documents are usually created by users as paper documents, portable document files (PDFs), scanned images or word processing files. See Table 1 for information on the file formats (e.g. .doc, .pdf) that are compatible with tDAR.
Datasets include faunal measurements, botanical data, radiocarbon dates or other, mostly numerical data.
Datasets are usually created by users as handwritten tables, punch cards, digital spreadsheets or database files. See Table 1 for information on the file formats (e.g. .xls, .accdb) that are compatible with tDAR.
Web forms guide dataset contributors through a streamlined process of metadata entry and file upload, including documentation of individual data table columns with mappings to coding sheets and ontologies. Coding Sheets and ontologies are two resource types available to support datasets and enable datasets to become more functional.
Images include survey overview photographs, plan view drawings, figures and other illustrative objects.
Images are usually created by users as film negatives, positive prints, drawings, digital photographs and digital raster or vector images. See Table 1 for information on the file formats (e.g. .jpg, .tiff) that are compatible with tDAR.
Sensory Data include laser scans, sonar, magnetometer or electrical resistivity data or other archaeological data recorded by sensory equipment.
Sensory Data are usually created by users in raster or text formats. See Table 1 for information on the file formats (e.g. .jpg, .tgz) that are compatible with tDAR.
Geospatial files include GIS files, shape files, personal geodatabases, and geo-rectified images. tDAR accepts a range of geospatial files at this point. Unlike documents, images, and other resource types, due to the complexity of geospatial files, one complete geospatial object (e.g., shapefile, or geotiff with associated world file, and project file) is associated with one resource within tDAR, this helps tDAR capture appropriate metadata for each file.
Coding sheets provide full descriptions and explanations of shorthand codes used in archaeological datasets or field notes. This information is critical for deciphering and making future use of data, records, notes, figure captions and other resources where idiosyncratic abbreviations are used.
An example would be a database or spreadsheet where the fields were named using short codes, either because of name length restrictions or data entry purposes (i.e. ARB = “Arbitrary Unit”).
Ontologies in tDAR refer to definitions of objects, concepts, and properties and relationships between them (such as typologies, cladistics or other taxonomic tools) and does not directly relate to the philosophical meaning of ontology.
Examples of tDAR ontologies would be artifact typologies showing the relative dates of projectile points at a site or biological cladistics showing the biological similarity of different fauna or flora recovered from middens or hearths.
Organizing Your Data
Before submitting your data to tDAR, organize your resources into groups based on some commonality. Useful organization strategies include grouping resources by:
In tDAR, Projects are a special kind of resource that group otherwise disparate resources together.
Projects are not necessarily analogous to archaeological excavations, but for discrete archaeological projects, it makes sense to group together excavation photos, site reports, level forms and artifact measurements under a tDAR Project named for the archaeological project.
The advantage of using a project to organize your resources is twofold:
Projects allow users to set general metadata at the project level. Resources that are grouped under a Project will “inherit” the Project-level metadata automatically, saving users from having to enter repetitious metadata at the Resource level. Resource level metadata can be customized for each resource, allowing more specific information to be used for individual files or resources.
For example, if all your resources deal with the period from 200-1450 A.D., you can set the Project “Temporal Coverage” field accordingly. Now every resource added to the project will be able to inherit the “Temporal Coverage” field from the Project, without needing to re-enter “200-1450 A.D.” for every resource. When a project is updated, all of the associated individual resources are automatically updated as well.
Projects allow users to move from the Resource level and find other resources from the same project.
For example, a user reading the Kennewick Man Cultural Affiliation Report might want to also see the DNA testing results. Seeing that the report is grouped under the Project title: “The Archaeology of Kennewick Man,” upon clicking on the Project title, the user is able to other associated resources such as letters from the U.S. Secretary of the Interior to the U.S. Army Corps of Engineers, radiocarbon dating results and -eureka!- the DNA testing results!
Collections are a convenient way to organize and display resources and to more easily manage permissions on groups of resources.
Collections can be stacked or nested to allow you to group and embed projects, independent resources, and other collections. As the diagram below shows, you can place any combination of projects, resources, and collections under a parent collection.
National Information Standards Organization
2004 Understanding Metadata. NISO Press. Bethesda, MD. Electronic version:
http://www.niso.org/publications/press/UnderstandingMetadata.pdf, accessed 6/29/2011.
tDAR currently supports eight kinds of resources: Documents, Datasets, Images, Sensory Data, Geospatial Files, Coding Sheets, Ontologies, and Projects, a special kind of resource that will be discussed later in this guide.