PA-SHARE Data Quality
This data quality statement is issued in November 2024. It will be reviewed and updated as PA-SHARE and its digital records continue to grow and evolve.
PA-SHARE is Pennsylvania’s State Historic & Archaeological Resource Exchange. Launched in 2021, it is an integrated web-based project management and cultural resources Geographic Information System (GIS). PA-SHARE includes a map-based inventory of the historic resources, archaeological sites, surveys, historical markers, and project-related information collected by the Pennsylvania State Historic Preservation Office (PA SHPO). PA-SHARE is the PA SHPO's chief storehouse of information and has replaced PA SHPO’s paper-based programs and file room. Data gathered in PA-SHARE enables the PA SHPO to fulfill its federal and state responsibilities most effectively and efficiently as well as prioritize actions to assist partners and the public in achieving preservation outcomes.
Data in PA-SHARE are reflective of the quality of the data submitted to PA SHPO. Historic resources and archeological sites within PA-SHARE may not include precise boundaries because of various sources and ages of mapped data and should be considered advisory for planning purposes, pending field verification. Data may be missing from a resource, project, survey, report, or marker record or entered incorrectly, particularly for older records that were digitized in preparation for PA-SHARE’s launch in 2021.
Absence of data does not necessarily indicate absence of resources or other project-related information. PA-SHARE subscription type will dictate the extent to which resource, survey, and report record and map data is visible to the subscriber. Regardless of subscription type, only project contacts can view project records.
Frequency of Data Updates
The amount and type of data in PA-SHARE changes continuously as new records are added and as new information related to a historic resource, archaeological site, project, survey, report, or historical marker is updated. PA-SHARE data is not static and is subject to change. When exporting data from PA-SHARE, either from a search or as a project or resource record, that data is only reflective of that point in time.
Archaeological Sites
Archaeological sites are added to the Pennsylvania Archaeological Site Survey (PASS) whenever site information is received from any source. There has not been a full systematic archaeological survey of the Commonwealth. Environmental data for archaeological sites are often extrapolated from maps. Locations are not field verified by SHPO personnel prior to inclusion. Site information frequently reflects only the initial investigation of the site. Information from subsequent excavations is added when provided, but many researchers do not submit updated information.
To be included in PA-SHARE, sites must meet PHMC’s Site Identification Criteria and will be assigned a Smithsonian trinomial, which PA SHPO refers to as a PASS number, formatted as 36XX0000 where 36 represents Pennsylvania, the two-letter code is the county designation, and the four numbers represent the sequence number of the site within the county. Legacy isolated finds and non-site collections are designated by 36XX/000. These are generally locations where individual diagnostics were found, or where materials were collected that do not meet the site criteria but were included in the curated collections from a project. Since the launch of PA-SHARE in 2021, pre-contact diagnostic isolated finds are assigned a standard trinomial. Non-site collections are no longer mapped or issued site numbers but continue to be curated by the State Museum of Pennsylvania.
All archaeological sites that had map locations that provided locational data have been mapped. All boundaries should be considered approximate unless the site has been fully excavated. Any site shown on the map as a small circle is represented by only a center point. This was very common on early records. Approximately 140 records have no locational information.
Statewide Pre‐Contact Probability Model
The Pennsylvania Department of Transportation (PennDOT), in partnership with The Federal Highway Administration (FHWA), through a research grant, and in coordination with Pennsylvania State Historic Preservation Office (PA SHPO), developed The Statewide Pre-Contact Probability Model (Model). PennDOT contracted with URS Corporation (now AECOM) to develop the Model with the intent to provide better data to regional transportation organizations (i.e., metropolitan planning organizations [MPOs] and rural planning organizations [RPOs]) to aid in decision-making as part of PennDOT's Linking Planning & NEPA (now known as PennDOT Connects).
The Model involved developing statistical models to analyze the landscape at known pre-contact Native American archaeological sites in Pennsylvania and extrapolating identified patterns to all areas of the Commonwealth of Pennsylvania. Due to the variability of environments and pre-contact Native American cultures throughout Pennsylvania, many different models were produced for different areas. One of the major accomplishments of the Model is a complete statewide layer of archaeological sensitivity aggregated from 132 spatial subareas. The Model only evaluates the potential for pre-contact sites and does not fully account for previous earth disturbance. The probability of the presence of contact period and historic archaeological sites should still be evaluated using historic documentation.
The Statewide Pre-Contact Probability Model Geographic Information System (GIS) layer is available to Basic PA-SHARE users with archaeological privileges and to Pro and Business users regardless of their privileges. This Model layer is intended to be used as a planning tool in concert with other planning tools and is not a substitute for consultation with the PA SHPO, nor is it a substitute for site-specific professional judgment.
Because the individual sub-models do not account for modern development, the probability layers that have been generated should always be viewed on base maps of aerial photography as well as any other documentation of disturbances. In addition, the PA SHPO does not treat the model as absolute, as it requires on-the-ground testing in various parts of the state.
Above Ground Resources
Above ground resource information is received from many sources: municipal surveys, environmental review surveys, thematic studies, and individual property submissions for environmental review or National Register consideration. Not all of Pennsylvania's 67 counties have been systematically surveyed. New above ground resources are entered and mapped when received and new surveys received electronically may have a delay in the uploading process for data verification and conversion.
Data associated with above ground resources include property and cultural information that was captured by the person documenting the historic resource. Data reflects the condition and known information of the above ground resource at time of recordation. The completeness of the locational data varies by county.
Mapping of above ground resources has fluctuated over the years. Prior to 1996, each building had its own number and mapping. Between 1996 and 2020, only the resource that would be evaluated for the National Register of Historic Places was mapped and given a Key number. This means that, in the case of a district, the district boundaries would be mapped, not the individual buildings on the inventory. PA SHPO actively consolidated some of these older districts and removed the individual mapping. With PA-SHARE, PA SHPO has returned to mapping individual buildings. As a result, some districts will show all their "child resources," meaning the individual buildings, and some will not.
Archaeological and Historic Survey and Reports
The Reports data set includes many types of documents that describe cultural resource management work. Surveys are a set of data that involve investigations at particular places, which may result in a Report.
Most of the legacy reports in PA-SHARE are the result of environmental review surveys. These reports are identified by their legacy project file "ER Numbers" which have a format of YYYY-NNNN-CCC-A; the first 4 digits are the year the project started, the second four are a sequence number within that year, the next three are the county code, and a final (optional) letter indicates the submission within that project.
Other report types include reports from regional surveys, multiple property nomination (thematic) documentation, historic context documents, and research papers.
Only Phase I archaeological surveys, geomorphological reports, negative survey forms, and records of disturbance were mapped. Since Phase IIs and IIIs are, by definition, within recorded sites, these reports were not mapped. Quality and granularity of the mapping is dependent upon the quality of the original mapping. Older reports tend to show only generalized areas. Newer reports will have specific testing areas mapped.
Historic Resource Survey Reports often cover entire municipalities or even counties and, therefore, were not mapped in the previous GIS system. Since the transition to PA-SHARE in 2021, surveys in progress are mapped to cover the entire geographic area being surveyed. Once survey work is completed, survey mapping is updated to only the resources surveyed.
Historical Markers
The Historical Markers data set includes information related to the text on the marker, its date of installation, municipal locations, and subject matter categories. Mapping is based on points derived from the recorded latitude and longitude of the marker.
Projects
Legacy Project data for environmental reviews have been migrated from a system begun in the early 1980s and include limited information. These legacy projects were not mapped. Since the transition to PA-SHARE in 2021, all Areas of Potential Effect are mapped and visible to PA-SHARE subscription users as a map layer. Project mapping also includes other project types (DOE, NR, Tax Credit, Independent Surveys, Agreements/Grants) based on the boundary of the resource(s) associated with the project.
