Connecticut 2004 Aerial Photo Center Point Index is a point feature class that defines the center point for each Connecticut 2004 orthophoto image tile. There are 3,413 orthophoto tiles and these data include a center point for each orthophoto tile. Each tile measures approximately 1.17 miles east-west by 1.5 miles north-south, covering a geographic area of approximately 1.755 square miles. The orthophotos are organized in a grid pattern that covers the State of Connecticut with 36 orthophoto tiles per 7.5 minute quadrangle area (9 per 3.75 minute quarter quadrangle area). The overlap between adjacent photos is approximately 350 to 450 feet. Each center point feature is identified by a unique ORTHOPHOTO_TILE value, which matches the name of the corresponding image file.
These data serve as a center point index to the set of 2004 orthophoto image tiles for Connecticut.
Date of photography
None. No restrictions or legal prerequisites for using the data after access is granted. The data is suitable for use at appropriate scale. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Departments of Environmental Protection and Transportation as the source for this information. For example, include the following data source description when printing this layer on a map: Photo centers - From the Connecticut 2004 Aerial Photo Center Point Index layer, published by CT DEP and CT DOT.
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All attributes have valid values. Values are within defined domains. No rigid attribute accuracy tests were conducted. However, assignment of quadrangle number, quadrangle name, and quadrangle section values were conducted through spatial joins with previously quality checked quadrangle and quarter quadrangle index spatial data, followed by a visual inspection for expected results to ensure overall accuracy.
Point features conform to the following topological rules. Points are single part. There are no duplicate points. Points do not overlap. Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to derive these center point features from a photo index in CAD format supplied by the State of Connecticut, Department of Transportation. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.
The completeness of the data reflects the feature content of the data sources, which is photo index for the 2004 orthophotos in CAD format from the State of Connecticut, Department of Transportation.
The horizontal positional accuracy of this data is unknown.
Quarter_Quadrangle_Index_NAD83_Area.shp is in ESRI Shapefile format with polygon features.
These data serve as a center point index to the set of 2004 orthophoto image tiles for Connecticut.
Orthophoto tile boundary information in CAD format from the State of Connecticut Department of Transportation (source 1) was used as the basis for creating a center point feature for each orthophoto tile. Attributes such as ORTHOPHOTO_TILE were transferred from the polygon data in CAD format to individual point features. Additional center point attribute information such as quadrangle number, quadrangle name, and quadrangle section values were subsequently determined and assigned to individual point features through spatial joins with quarter quadrangle index spatial data published by the State of Connecticut, Department of Environmental Protection (source 2). The resulting point feature class was named Ortho_2004_Index_Point (source 3).
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Internal feature number.
ESRI
Feature geometry.
ESRI
Information encoded about photo center point features includes the name of the corresponding orthophoto image tile (ORTHOPHOTO_TILE) and identification of the quadrangle number (QUAD_NO), quadrangle name (QUADRANGLE) and quadrangle section (QUAD_SEC) the orthophoto is located on. A point feature is located in the center of each tile area.
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Although these data have been used by the State of Connecticut no warranty, expressed or implied, is made by the State of Connecticut 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 Connecticut 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.
The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.
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