PAMAP Vector Data
The vector framework layers of the Pennsylvania Spatial Data Infrastructure (SDI) are developed through the PAMAP collaboration approach and are based on existing digital map resources developed by state and federal agencies, counties, regional agencies, and municipalities. The PAMAP/SDI vector framework data layers are:
- Road centerlines
- Other transportation (rail, air, etc.)
- Political boundaries
- Geodetic monuments
- Land cover
The PAMAP vector development program is not as advanced as the imagery, elevation, and land cover elements, due to the collaborative nature of the effort, the large number of data providers, and issues associated with aggregation of data from many sources. The promise of statewide vector layers developed from the best and most accurate data has not yet been achieved. The vector program currently consists of available statewide data layers from varied sources and the first issue of statewide data from county sources. These data may be improved over time using additional data providers or by updating spatial alignment, structure, currency, and/or content.
All counties have provided data to the PAMAP Program. All County Cooperative Agreement partners (55 total) were asked to provide one or more of the following data layers. In addition, non-Agreement counties (12 total) receiving PAMAP lidar and/or imagery data were asked upon data delivery to provide one or more of the following data layers. This collection will continue in 2010 as lidar and imagery data are finished for each county. The requested data layers include:
- Buildings. Point (location) and/or polygon (outline).
- Hydrography. Single-line streams, double-line streams, water bodies (polygons).
- Road Centerlines. Single-line roads.
- Railroads. Single lines.
- Political boundaries. County and municipal boundaries.
Some counties were able to supply all layers, while other counties were able to supply just 1 or 2 layers. No quality assessment was performed on any of the data. There is considerable diversity on source, accuracy, structure, completeness, and content. For example, one county's hydrography data may have originated with a photogrammetric project, while another's data may have originated from an existing statewide layer. Some data within a layer (e.g. roads) may have attribute data (names, addresses) but other data may have limited or no attributes.
Statewide feature classes were finalized after initial review and cross-reference of the provided data. The Vector Demonstration Project (VDP) data schema was used for the first review of the data. The county data structure and content was compared to the schema to determine how well the data would populate the proposed database. The county data structure and content was also compared to the PGDSS version 2.5 schema to determine how well the data would match PGDSS content. These comparisons illustrated that relatively little of the VDP and PGDSS schemas would be populated (consistently or not) with the county-provided data. Consequently, a more limited data schema was used for each of the layers. The resulting database is still diverse for source data structure, content, accuracy, and completeness.
This data is provided to DCNR's GIS Coordinator and the Commonwealth's GIO for use by state agencies and others as directed. The data is also expected to be available through PASDA in 2010.
The PAMAP statewide vector framework data layers are available from varied sources. These data may be improved over time using additional data providers or by updating spatial alignment, structure, currency, and/or content. The current data sources are:
Road centerlines. PennDOT provides statewide layers of state-maintained roads and local roads, provided through the Pennsylvania Spatial Data Access Clearinghouse (Clearinghouse or PASDA). PennDOT road data is being re-aligned to match PAMAP imagery. Current TeleAtlas North America (TANA) road data can be used by all Commonwealth government organizations, first responders, RCTTFs, regional planning organizations, K-12 schools and districts, and contractors/consultants doing work for these organizations . Information on the TeleAtlas data can be found at http://www.gis.state.pa.us and searching for TeleAtlas License Agreement. Road data from other providers can be found using the Clearinghouse's Data Access Wizard and the Transportation theme.
Railroads. A statewide railroad layer is available from the Clearinghouse. Railroad data from other providers can be found using the Data Access Wizard with the Keyword ‘railroad'. A national railroad layer can be found at the USGS National Atlas.
Buildings . There is no statewide buildings (structures) data. PAMAP LiDAR and imagery data may be used to develop a statewide building point and/or outline layer. Many counties have building footprint or structure point data. Some of this data may be downloaded using the Clearinghouse's Data Access Wizard using the Man-Made Structures theme or Keyword ‘buildings'.
Hydrography. The National Hydrography Dataset (NHD) is the statewide hydrography data. This data is maintained by the Department of Environmental Protection (DEP) in conjunction with the United States Geological Survey (USGS). The NHD is currently medium resolution (1:24,000 scale). The NHD data may be acquired from the Clearinghouse using FTP. Information about NHD can be found at http://nhd.usgs.gov or by viewing NHD metadata. The production of the high-resolution elevation data statewide may lead to the eventual development of a more sophisticated NHD layer for Pennsylvania . For the moment, funds are not available for such a development, and the technical challenges have not been worked out.
Political boundaries. PennDOT provides statewide boundaries of many political subdivisions, including counties and municipalities. This data is periodically updated with boundary updates provided by government organizations.
Geodetic monuments. PennDOT's Bureau of Design, Photogrammetry and Surveys Section maintains and provides statewide geodetic control and monument information. Geodetic monument data can be found at the Photogrammetry Asset Management System website (www.penndotpams.org).
Land cover. A prototype statewide land cover layer has been developed by the PAMAP Program using a combination of PAMAP and satellite imagery.