Topographic Contours 2024 - Download

This downloadable zip file contains an ESRI File Geodatabase (FGDB) that is compatible with most versions of ArcGIS Pro, ArcMap, and AutoCAD Map 3D or Civil 3D. To view the geodatabase’s contents, please download the zip file to a local directory and extract its contents. This zipped geodatabase will require approximately 1.38 GB of disc space (1.49 GB extracted). Due to its size, the zip file may take some time to download. This downloadable file geodataase (FGDB) includes Topographic Countours and Spot Elevations derived from LiDAR collected in spring of 2024 by Dewberry Engineers in coordination with Tallahassee - Leon County GIS. The contours were extracted at a 2 foot interval with index contours every 10 feet. Lidar Acquisition Executive Summary The primary purpose of this project was to develop a consistent and accurate surface elevation dataset derived from high-accuracy Light Detection and Ranging (lidar) technology for the Tallahassee Leon County Project Area. The lidar data were processed and classified according to project specifications. Detailed breaklines and bare-earth Digital Elevation Models (DEMs) were produced for the project area. Data was formatted according to tiles with each tile covering an area of 5000 ft by 5000 ft. A total of 876 tiles were produced for the project encompassing an area of approximately 785.55 sq. miles. The dataset was created by TLCGIS from lidar data acquired by a Riegl CQ-1560i lidar system from January 14, 2024 through January 19, 2024. ORIGINAL COORDINATE REFERENCE SYSTEM Data produced for the project were delivered in the following reference system. Horizontal Datum: The horizontal datum for the project is North American Datum of 1983 with the 2011 Adjustment (NAD 83 (2011)) Vertical Datum: The Vertical datum for the project is North American Vertical Datum of 1988 (NAVD88) Coordinate System: NAD83 (2011) State Plane Florida North (US survey feet) Units: Horizontal units are in U.S. Survey Feet, Vertical units are in U.S. Survey Feet. Geiod Model: Geoid12B (Geoid 12B) was used to convert ellipsoid heights to orthometric heights).本可下载的ZIP压缩包内含ESRI文件地理数据库（ESRI File Geodatabase，FGDB），可兼容绝大多数版本的ArcGIS Pro、ArcMap以及AutoCAD Map 3D或Civil 3D软件。若需查看该地理数据库的内容，请将此压缩包下载至本地目录并解压。该压缩地理数据库压缩后占用空间约1.38 GB，解压后占用空间约1.49 GB。由于文件体积较大，下载过程可能耗时较久。本可下载的文件地理数据库（FGDB）包含由Dewberry工程师于2024年春季与塔拉哈西-里昂县地理信息系统（Tallahassee - Leon County GIS）协作采集的激光雷达（LiDAR）数据衍生的地形等高线（Topographic Contours）与高程点（Spot Elevations）。本次生成的等高线间距为2英尺，每10英尺设置一条索引等高线。 激光雷达采集执行摘要 本项目的核心目标是为塔拉哈西-里昂县项目区域构建一套基于高精度激光探测与测距（Light Detection and Ranging，lidar）技术的统一且精准的地表高程数据集。所有激光雷达数据均按照项目规范进行处理与分类。项目区域内已生成详细的断裂线（breaklines）与裸地数字高程模型（Digital Elevation Models，DEMs）。数据按瓦片（tiles）格式进行组织，单个瓦片覆盖范围为5000英尺×5000英尺。本项目共生成876个瓦片，覆盖总面积约785.55平方英里。本数据集由TLCGIS基于Riegl CQ-1560i激光雷达系统于2024年1月14日至1月19日采集的激光雷达数据构建而成。 原始坐标参考系统 本项目产出的数据采用如下参考系统： 水平基准面：本项目采用2011年修正版1983北美基准面（North American Datum of 1983 with the 2011 Adjustment，NAD 83 (2011)） 垂直基准面：本项目采用1988北美垂直基准面（North American Vertical Datum of 1988，NAVD88） 坐标系：NAD83 (2011) 佛罗里达州平面北坐标系（US survey英尺） 单位：水平坐标与垂直坐标单位均采用美国测量英尺（U.S. Survey Feet）。 大地水准面模型：采用Geoid12B（大地水准面12B）将椭球高转换为正高。