Information used to reference the data.
Title: Connecticut 5 ft Contours (Revised)
Originators: State of Connecticut, Department of Environmental Protection (editor and publisher)
University of Connecticut, College of Agriculture and Natural Resources (compiler and editor)
State of Connecticut, Department of Public Safety
State of Connecticut, Department of Transportation
Connecticut Joint Highway Research Council
Publisher: State of Connecticut, Department of Environmental Protection
Publication place: Hartford, Connecticut, USA
Publication date: 20110502
Data type: vector digital data
A characterization of the data, including its intended use and limitations.
Abstract: Connecticut 5 ft Contours (Revised) is line feature-based data representing ground elevation at 5 foot intervals for the state of Connecticut. This data replaces the 5 ft contour data previously available from CT DEP. It has fewer errors and data gaps than the previously available contours; however, some inaccuracies remain. These contour lines have been processed to appear smoother and less jagged than the previous data and have been optimized for faster drawing and performance. The source for these data is the Connecticut LiDAR 10-foot DEM (file name: ct_lidar) from the Center for Land Use Education and Research at the University of Connecticut, College of Agriculture and Natural Resources.
Purpose: Connecticut 5 ft Contours (Revised) is used to depict ground elevation at 5 foot intervals or greater. Each contour line represents a line of equal elevation and indicates surface relief when used with other information such as aerial photography, soils, geology, or hydrography.
Dataset credit: Aero-Metric, Inc. of Sheboygan, Wisconsin was contracted by the State of Connecticut to provide the 2004 Statewide Aerial Survey of Connecticut. Contract deliverables include digital orthohotos, two sets of non-rectified prints for stereoscopic viewing, photo indexes, and LiDAR data. All 2004 Statewide Aerial Survey imagery and data products are defined under State of Connecticut contract award number RFP-990-A-14-0518-C (dated Feb 22, 2000), including contract award supplement #1 (dated Feb 28, 2002), contract award supplement #2 (dated Nov 4, 2004), contract award supplement #3 (dated Nov 26, 2004) and contract award supplement #4 (dated May 13, 2005). TerraPoint LLC of Woodlands Texas was subcontracted to create a Connecticut Statewide LIDAR dataset.
The University of Connecticut, College of Agriculture and Natural Resources subsequently created and made accessible a variety of LiDAR-derived datasets. One of these, the Connecticut LiDAR 10-foot DEM (file name: ct_lidar), was used to create the smoothed statewide DEM from which this revised contour line feature class was created.
Language of dataset: en
Contact information for the individual or organization that is knowledgeable about the data.
Organization: State of Connecticut, Department of Environmental Protection
Person: Howie Sternberg
Phone: 860-424-3540
Fax: 860-424-4058
Email: dep.gisdata@ct.gov
Hours of service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time
Address type: mailing and physical address
Address: 79 Elm Street
City: Hartford
State or Province: CT
Postal code: 06106-5127
Country: USA
How the data are represented, formatted and maintained by the data producing organization.
File or table name: depgis.DEP.CONTOUR_2000_5FT
Data type: vector digital data
Data format: SDE Feature Class
Native dataset environment: Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.6.1500
Time period(s) for which the data corresponds to the currentness reference.
Date: 2000
Currentness reference: ground condition
The state of and maintenance information for the data.
Data status: Complete
Update frequency: None planned
Words or phrases that summarize certain aspects of the data.
Theme:
Keywords: LiDAR, contours
Keyword thesaurus: none
Theme:
Keywords: elevation, environment
Keyword thesaurus: ISO 19115 Topic Cateogry
Place:
Keywords: Connecticut, CT
Keyword thesaurus: U.S. Department of Commerce, 1987, Codes for the Identification of the States, the District of Columbia and the Outlying Areas of The United States, and Associated Areas (Federal Information Processing Standard 5-2): Washington, DC, National Institute of Standards and Technology.
Place:
Keywords: United States of America, USA
Keyword thesaurus: U.S. Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions (Federal Information Processing Standard (FIPS) 10-4): Washington, D.C., National Institute of Standards and Technology.
Restrictions and legal prerequisites for accessing or using the data after access is granted.
Access constraints: None. No restrictions or legal prerequisites for accessing the data. The data is in the public domain and may be redistributed.
Use constraints: The data is suitable for use at appropriate scale; however, these data are not consistently accurate statewide. Users should review the following description of source data and process steps in order to determine the appropriate uses of this information.
The original data source was 20-foot posting LiDAR point data collected in 2000, which has a horizontal positional accuracy of approximately 3 feet on the ground. The LiDAR point data has known limitations including data gaps. While the contour lines previously available from CT DEP were derived directly from the LiDAR point data, these contour lines were derived from the Connecticut LiDAR 10-foot DEM (file name: ct_lidar) from the Center for Land Use Education and Research (CLEAR) at the University of Connecticut, College of Agriculture and Natural Resources. During the production of the Connecticut LiDAR 10-foot DEM, CLEAR manually edited the data to fill in data gaps with coarser data based on contour lines from USGS topographic maps. Therefore, these contour lines contain fewer errors than the previously available contour lines.
In order to produce less jagged contour lines, a circular averaging filter with a radius of 3 cells was applied to the Connecticut LiDAR 10-foot DEM (file name: ct_lidar). The contour lines were produced from this smoothed DEM. Visual inspection has shown that the resulting contour lines align well with the contour lines previously available from CT DEP.
These contour lines, while less error-prone than the previous data, retain some errors from the LiDAR point data and may have other errors introduced during the editing and processing steps. Contour lines may not conform well to the shoreline of waterbodies and in many instances erroneously extend into areas of water. Due to these anomalies, use caution when viewing and analyzing this information.
There are no restrictions or legal prerequisites for using the data after access is granted. Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Conneticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing these data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut as the source for this information.
Data Security Information
Handling restrictions imposed on the data because of national security, privacy or other concerns.
Security classifiction system: None
Security classification: None
Security handling: No restrictions for handling the data