Connecticut 1 Ft Contours

Contours are lines of equal elevation. This is a contour feature layer for the state of Connecticut derived from the index contour in the 1' contour data set. All closed polygons less than 35' length have been deleted to improve loading performance. This data set is derived from the 2023 Lidar with15 to 20 points per meter squared. Source: 1 foot contours were generated for each production block from the final bare earth DEMs using ArcGIS software. Contours are labeled as intermediate or index with index contours set to every 10th interval. Using ArcGIS software, the contours were validated for correct topology, including must not intersect, must not self intersect, and must not have dangles. Contours are then manually reviewed with the 3D breaklines to ensure complete coverage, correct coding, data integrity and that contours behave correctly around water bodies, water crossings, and elevated features such as overpasses. The contours are then clipped to individual tiles as creating one dataset for the entire project renders the feature class un-usable. Enclosed contours completely within building footprints were removed from the final contour dataset. Coordinate System: 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) Contours were cut by Town then merged into COGs Geographic Extent Coverage: State of Connecticut Classifications Sensitivity: Public Usage: Public Use Quality: High Quality Known Quality Issues: None known, but subject to standard limitations of third-party commercial data Currency Created: 2023 Update Frequency: Per Flight Last Updated: August 2023等高线（Contours）为高程等值线。本数据集为康涅狄格州的等高线要素图层，源自1英尺（1'）等高线数据集中的索引等高线。所有长度小于35英尺（35'）的闭合多边形均已被删除，以提升加载性能。 本数据集基于2023年激光雷达（Lidar）数据生成，每平方米覆盖15至20个激光点。 数据来源：使用ArcGIS软件，从最终的裸地面数字高程模型（DEMs）为每个生产区块生成1英尺等高线。 等高线被分为间曲线（intermediate contour）与计曲线（index contour）两类，其中计曲线每10个等高距绘制一次。使用ArcGIS软件对等高线进行拓扑正确性验证，验证规则包括不得交叉、不得自相交以及不得存在悬挂节点（dangles）。随后结合三维断裂线（3D breaklines）对等高线进行人工复核，以确保数据覆盖完整、编码正确、数据完整，并保证等高线在水体、过水通道以及立交桥等高架设施周边的形态符合要求。 随后将等高线裁切为独立瓦片，因为为整个项目生成单一数据集会导致要素类无法正常使用。最终等高线数据集中已移除完全位于建筑轮廓（building footprints）内的闭合等高线。 坐标系统：本数据采用的水平基准面/投影为NAD83（2011）、康涅狄格州平面坐标系（State Plane Connecticut），单位为美国测量英尺（U.S. Survey Feet）；垂直基准面为NAVD88（GEOID18）。等高线按城镇裁切后合并为云优化GeoTIFF（COGs）格式。 地理覆盖范围：康涅狄格州 分类敏感度：公开 使用权限：公开使用 数据质量：高质量 已知质量问题：暂无已知问题，但需遵循第三方商业数据的标准限制 数据创建时间：2023年 更新频率：随飞行任务更新 最后更新时间：2023年8月