Pennsylvania Spatial Data Access

Abstract:

The City of Philadelphia has migrated metadata for this data set to the City-wide Metadata Catalog. For any questions about the migration and administration of the Metadata Catalog, please contact maps@phila.gov. To view the metadata for this layer, please visit:http://metadata.phila.gov/#home/datasetdetails/5696bec037a762966e837b49/representationdetails/5696bf4c006891480aabbe39/

Purpose:

The lidar dataset was collected to be utilized for the creation of a digital elevation model and 1ft contours. Other uses expected. Lidar Data Products for the Philadelphia, PA collection area including a 5ft Digital Elevation Model (DEM), and tiled1ft Contours.

Currentness_Reference:

Publication Date

Use_Constraints:

See access and use constraints information.

Address:

100 Town Centre Drive, Suite A

Logical_Consistency_Report:

Visual checks were used to make sure all features and feature classes are complete.

Completeness_Report:

Visual checks were used to make sure all features and feature classes are complete.

Process_Description:

Terrain, DEM, and 1ft Contours: For the Bare Earth Data, the Lidar Point Data was converted to a Multipoint feature class, with a filter for Ground (class 2). Breaklines for hydrographic features were digitized from the intensity values of the lidar data. The hydrographic features, include water bodies (> 0.5 Acre), wide rivers (> 5m wide), and an artifical path representing the centerline of the wide rivers. Elevation values from the lidar data were conflated to the “z-values” of the features at 5ft intervals from the lidar data using QCoherent’s LP360 software. Elevation values were conflated to the Stream Centerline Breaklines at 5ft intervals with a downstream constraint algorithm. After the centerlines were conflated, a script was used to copy the elevation values from the artificial path to the surrounding double line stream polygons, which acts to essentially flatten the wide river from stream bank to stream bank. Elevation values for the water body polygons were added as an attribute to the feature class based on the minimum lidar elevation value along the shoreline of the water body. The multipoint feature class and breakline feature classes were used to create a Ground terrain for the collection area. The terrain was converted to a DEM with 5ft cell resolution. The contours were created from the DEM. The contours were edited in the following manner: Lines shorter than 30ft (1.5 raster cells) were deleted. The contour lines were smoothed using a PAEK algorithm with a 3m smoothing tolerance. Attributes were added for 10ft, 20ft, and 50ft Index contours. A Lidar Tile Index Feature Class was created for the original lidar files. A hillshade was also created for the DEM using default ESRI illumination parameters.

Attribute_Definition:

Internal feature number.

Attribute_Definition_Source:

Esri

Attribute_Definition:

Feature geometry.

Attribute_Definition_Source:

Esri

Attribute_Definition:

Length of feature in internal units.

Attribute_Definition_Source:

Esri

Address:

Not available

Distribution_Liability:

See access and use constraints information.

Address:

115 Land and Water Building

Distribution_Liability:

The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.

Address:

17 Highland Dr

2015 Topographic Contours 1ft