表演的两倍

Author: Penny Boviatsou

More than 90 years ago, National Geospatial Information (NGI), a component of the Department of Rural Development and Land Reform (DRDLR), commenced with the establishment of an integrated survey system and provision of extensive mapping coverage of South Africa.

NGI也被称为南非国家地图机构，拥有可追溯到1926年的航空摄影和图像中最大，最广泛的档案，并拥有许多国家报道。随着时间的流逝，图像已经显着发展，自2008年以来，所有图像均以颜色（RGB）和颜色Infra-Red（CIR）的高分辨率数字传感器（CIR）获取。

2008年，NGI决定购买自己的Leica DMC I机载相机系统，并任命服务提供商代表其操作该系统。Geospace International是非洲领先的航空摄影服务提供商，成功招标并已由NGI任命为直到2016年的DMCI。GeospaceInternational还在2008年购买了自己的DMC Icaptured for NGI’s national mapping programme.

The mapping program started in 2008 and the aim was to cover the whole country (1.2 square kilometres) every three years at 50 centimetres Ground Sampling Distance (GSD) until the end of 2016. In 2017, NGI decided to start a new cycle of acquisition at 25 cm GSD covering the country. The demand for higher resolution imagery by the users of the data led to the change in resolution.

NGI uses the data to generate 1:10,000 orthophotos, covering South Africa every three to five years with the 25 cm GSD. The orthophotos are used to update the 1:50 000 topographical maps. The orthophotos are also made available at no cost to South African citizens and companies that need to use this data for their GIS or other applications.

广阔地图的独特解决方案

With the new direction from NGI to cover South Africa with 25 cm GSD imagery from 2017 onward, Geospace International decided to purchase the newLeica DMC III机载数码相机，基于所有专门针对机载应用程序设计的新CMO技术。作为Leica Realworld大面积空降构成捆绑包的一部分，该传感器将世界上最大的单个框架与最有效的后处理工作流程HXMAP结合在一起，对于此类项目至关重要。该解决方案提供了前所未有的图像质量和整体传感器的无与伦比的几何精度，该传感器使Geospace International能够使用最新技术执行新的25 cm GSD收购。

“ Leica DMC III的完整安装仅花了三天。我们的目标是使用Leica DMC I以与50 cm GSD项目相同的飞行高度以大致相同的飞行高度获取25 cm GSD图像，从而与以前大致相同。Leica DMC III允许我们这样做，”说Bernhard Jacobs, director at Geospace International.

Once Geospace International collects the 25 cm GSD RGB and CIR imagery for NGI, the calibrated imagery together with the post processed GPS/INS data are supplied to NGI. The national mapping agency of South Africa then goes through the process of performing aerial triangulation, elevation capturing and final orthophoto creation, using the Hexagon Geospatial Imagestation suite of products. The software provides high volume photogrammetry and production mapping tools, including project creation, orientation and triangulation from aerial and satellite imagery.

表演两次

Geospace International正在运营Aero Commander 690B双涡轮机。该团队由两个飞行员和两个摄像机操作员组成。

“轻加权的Leica DMC III使我们每天增加1.5小时的飞行时间。以前，我们不得不回来加油，对成本和时间产生影响。”雅各布斯说。

额外的燃料使Geospace International每天都可以覆盖更多的区域。DMC III的平均每天飞行时间为5.1小时和高性能，HXMAP的处理doubled the performance.

“现在，我们可以使用Leica DMC I以25 cm GSD的速度与Leica DMC III一起以50 cm GSD的速度飞行相同的工作，并以5％至10％的额外飞行时间飞行。在山区，我们飞行的飞行线数量与50 cm GSD的DMC I相同，以25 cm GSD覆盖该区域。

“The new DMC III has better overall radiometry and a more homogeneous quality across the complete block. We are impressed with the GPS/IMU results,”雅各布斯说。

空前的生产力

Geospace has covered more than 240,000 km2 at 25 cm GSD from July to November 2017, close to 50,000 releases, and three months ahead of schedule. The company aims to continue procuring imagery for NGI covering South Africa every three to four years.

“We would recommend the Leica Geosystems products and solutions to anyone in the aerial survey industry because of the quality, the excellent support given by the staff, and the overall durability and long-term use without problems when using the system,”雅各布斯说。