Penn State Data Commons - Full Metadata

Abstract:

High resolution land cover dataset for Howard County, MD. Seven land cover classes were mapped: (1) tree canopy, (2) grass/shrub, (3) bare earth, (4) water, (5) buildings, (6) roads, and (7) other paved surfaces.  The minimum mapping unit for the delineation of features was set at 96.83 square feet.  The primary sources used to derive this land cover layer were NAIP 2007 with a resolution of 3.28 square feet, 2004 LiDAR with a 3.28 square foot resolution, this LiDAR data was processed into an nDSM and an intensity layer which were both used in the classification. Ancillary data sources included GIS roads (Road_Polygon_Update), buildings (Buildings_all) and boundary (Boundary) data provided by Howard County.  Other GIS data used in the classification was utility lines (Utility_Lines), railroads (Railroads_poly) created by the Spatial Analysis Lab from NAIP 2007 imagery and LiDAR data.  Finally, surface water data (Surface_Water), edited from the National Hydrography Data Set was also used in the classification process. This land cover dataset is considered current as of 2009. Object-based image analysis techniques (OBIA) were employed to extract land cover information using the best available remotely sensed and vector GIS datasets.  OBIA systems work by grouping pixels into meaningful objects based on their spectral and spatial properties, while taking into account boundaries imposed by existing vector datasets.  Within the OBIA environment a rule-based expert system was designed to effectively mimic the process of manual image analysis by incorporating the elements of image interpretation (color/tone, texture, pattern, location, size, and shape) into the classification process.  A series of morphological procedures were employed to insure that the end product is both accurate and cartographically pleasing. No accuracy assessment was conducted, but the dataset was subject to a thorough manual quality control.  33,359 corrections were made to the classification.

Purpose:

This dataset was developed as part of the Urban Tree Canopy (UTC) Assessment for Howard County. As such, it represents a "top down" mapping perspective in which tree canopy over hanging other features is assigned to the tree canopy class. At the time of its creation this dataset represents the most detailed and accurate land cover dataset for the area.

Supplemental_Information:

This project was funded by the USDA Forest Service, Howard County, the Baltimore Ecosystem Study under grant DEB-0423476 from the National Science Foundation. The methods used were developed by the University of Vermont Spatial Analysis Laboratory with funding from the USDA Forest Service.

Currentness_Reference:

ground condition

Use_Constraints:

None

Address:

81 Carrigan Drive

Address:

Aiken Room 220

Data_Set_Credit:

University of Vermont Spatial Analysis Laboratory

Attribute_Accuracy_Report:

No accuracy assessment was conducted, but the dataset was subject to a thorough manual quality control (QC).  33,359 corrections were made to the classification.  Accuracy assessments from previous UTC land cover datasets indicate that the use OBIA techniques in combination with a detailed QC yield an overall accuracy of 95% or better.

Logical_Consistency_Report:

Valid raster dataset.

Completeness_Report:

Complete for Howard County based on 2007 boundaries.

Source_Contribution:

Building Footprints
Surface Water
RailRoad Polygons
Roads
Utility Lines

Process_Description:

Object based image analysis (OBIA) using a rule-based expert system

Process_Description:

Manual corrections to land cover classification

Process_Description:

Metadata imported.

Attribute_Definition:

Internal feature number.

Attribute_Definition_Source:

ESRI

Attribute_Definition:

Land cover code

Attribute_Definition_Source:

UTC