Management Summary The Caribbean Island state of Grenada seeks to update its national geospatial data by procuring Lidar elevation models and color/infrared aerial imagery for the entirety of its 380 km2 territory. This document describes the technical specifications for the data capture mission and data deliverables. It outlines the detailed requirements for the expected data quality (accuracy, resolution, completeness, classification etc.), acceptance criteria and reporting standards. The key requirements are: Area of Interest Land mass of the islands of Grenada, Carriacou and Petite Martinique as well as the smaller islands; Total area of 380 km2. Main products: Topographic Lidar data Aerial color (RGB) photography Aerial near infrared (NIR) photography Resolution and accuracy Topographic Lidar: min. 8 points per m2, 10 cm vertical RMSE, 20 cm horizontal RMSE Orthophotos: 20 cm GSD, 3 pixel horizontal RMSE Deliverables Classified point cloud Interpolated topographic digital surface model (DSM) as 0.5 m grid Interpolated topographic digital terrain model (DTM) as 0.5 m grid DTM contours, 0.5 m interval RGB orthophoto mosaic with 0.2 m resolution Color infrared orthophoto mosaic with 0.2 m resolution DTM adjusted and combined with bathymetry data provided by the Contracting Authority Reference systems Delivery system 1: WGS84 datum, ITRF2008 reference frame, UTM Zone 20 North projection, orthometric heights over EGM2008 Delivery system 2: Grenada 1953 datum (Clarke 1880 ellipsoid), British West Indies Grid projection (EPSG 2003), orthometric heights over EGM2008. Precise datum transformation parameters and a detailed geoid model are in the process of being established under a parallel project and will be made available to the Contractor in due time. Measurement unit = meters
tropical storm or even hurricane. The best season for airborne data capture missions is the dry season with prevailing easterly Trade Winds in the months February through April. See Figure 4 for details. Figure 4: Rainfall statistics for Grenada. Source: Product Summary of Key Deliverables The following table gives a high-level summary of the key products to be delivered by the contractor under this project. The detailed requirements for the data collection, individual products, reporting and quality assurance/quality control documentation will be described in chapters 4 to 7. Product Types Product Specification Deliverables Format(s) Resolution Topographic Lidar Delivery coordinate system 1: WGS84, UTM Zone 20 N, orthometric heights using the EGM2008 geoid model Delivery coordinate system 2: Grenada Datum 1953, British West Indies Grid projection, local orthometric heights Vertical accuracy 20 cm @ 95% CI, horizontal accuracy 40 cm @ 95% CI Classified Lidar point cloud Lidar intensity images Digital Surface Model (DSM) Digital Terrain Model (DTM) Contours LAS TIFF + TFW TIFF + TFW TIFF + TFW ESRI Shape Min. 8 0.50 m 0.50 m 0.50 m 1 m Aerial imagery RGB + NIR Delivery coordinate system 1: WGS84, UTM Zone 20 N, orthometric heights using the EGM2008 geoid model Delivery coordinate system 2: Grenada Datum 1953, British West Indies Grid projection, local orthometric heights Horizontal accuracy of the Orthophoto product 60 cm @ 95 % CI Single aerial images RGB + NIR Adjusted image centers and orientation parameters (result of aerotriangulation) Orthophoto mosaic RGB + NIR 3 x 8 bit TIFF ESRI Shape 3 x 8 bit TIFF + TFW GSD max. 0.20 m n/a 0.20 m Combined Topographic/Bathymetric Elevation Height differences between ground DTMs Complete seamless DTM and contours including both bathymetry (provided by UKHO) and topography (collected under this contract) Topo-Bathy difference model Seamless DTM mosaic Seamless contours TIFF + TFW TIFF + TFW ESRI Shape 1 m 1 m 1 m Ancillary Information Deliver all additional technical data gathered to support the project Flight line trajectories Lidar strip ESRI Shape TIFF + TFW RINEX
Appendix C - UKHO Bathymetry Project Information UKHO Lidar Survey Specification, May 2016: Survey Specification V1.1 - Lidar.pdf Hydrographic Instruction “Grenada and St Vincent and the Grenadines – Lidar”, HI 1530, Version 1, 2nd August 2016: HI_1530_CMEP_GRD_SVG_Lidar_PJP.pdf