2D Building Footprints

<div style='background-color:rgb(255, 255, 255); border:0px solid currentcolor; box-sizing:border-box; color:rgb(74, 74, 74); font-family:&quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size:16px; font-style:normal; font-variant-caps:normal; font-variant-ligatures:normal; font-weight:400; letter-spacing:normal; line-height:1.5; text-align:start; text-decoration-color:initial; text-decoration-style:initial; text-indent:0px; text-transform:none; word-spacing:0px;'><div style='background-color:rgb(255, 255, 255); border:0px solid currentcolor; box-sizing:border-box; color:rgb(74, 74, 74); font-family:&quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size:16px; font-style:normal; font-variant-caps:normal; font-variant-ligatures:normal; font-weight:400; letter-spacing:normal; line-height:1.5; text-align:start; text-decoration-color:initial; text-decoration-style:initial; text-indent:0px; text-transform:none; word-spacing:0px;'><p>Connecticut Statewide Building footprints were created during the CT Statewide GIS Services lidar project. Building footprints are reviewed against lidar intensity imagery to verify completeness of capture.</p><p>&nbsp;</p><p><strong>Dataset Description:</strong></p><p>&nbsp;</p><p>The data was developed based on a horizontal datum/projection of NAD83 (2011), State Plane Connecticut, U.S. Survey Feet and vertical datum of NAVD88 (GEOID18), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 23,381 individual 2,500 ft x 2,500 ft tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 2,500 ft x 2,500 ft schema. Maximium Surface Height Raster and Swath Separation Image tiles 025645_se, 080655_ne, 085655_ne, 085655_nw, 090655_nw, 110660_se, and 135665_se do not exist in the deliverables due to all of the points in the cooresponding LAS tiles being flagged as withheld. LAS file 110660_se is all water and contains no lidar returns, this file does not exist in the deliverables.</p><p><strong>Ground Conditions:</strong></p><p>Lidar was collected in Spring 2023, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Dewberry established a total of 38 ground control points that were used to calibrate the lidar to known ground locations established throughout the CT Statewide GIS Services project area.</p><p>An additional 247 independent accuracy checkpoints, 145 in Bare Earth and Urban landcovers (145 NVA points), 102 in Tall Grass and Brushland/Low Trees categories (102 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data</p><p><strong>Geographic Extent</strong></p><ul><li>Coverage: State of Connecticut</li></ul><p>&nbsp;</p><p><strong>Classifications</strong></p><ul><li>Sensitivity: Public</li><li>Usage: Public Use</li><li>Quality: High Quality</li><li>Known Quality Issues: None known, but subject to standard limitations of third-party commercial data</li></ul><p>&nbsp;</p><p><strong>Currency</strong></p><ul><li>Created: 2023</li><li>Update Frequency: Per Flight</li><li>Last Updated: August 2023</li></ul><p style='text-align:center;'><span style='color:#000000; font-family:Verdana; font-size:13px;'><i><span style='display:inline !important; float:none; font-style:normal; font-variant-caps:normal; font-variant-ligatures:normal; font-weight:400; letter-spacing:normal; text-align:start; text-decoration-color:initial; text-decoration-style:initial; text-indent:0px; text-transform:none; word-spacing:0px;'><strong>Building Layer will be updated after the completion of the 2026 flight.</strong></span></i></span></p></div></div>

Tags: 2023, connecticut, ct, ct-gis, ct-gis-office, elevation-data, gis, opm
Organization: State of Connecticut