I. Overview
Guangdong, the name evolved from Lingnan East Road and Guangnan East Road, referred to as "Guangdong", the provincial capital Guangzhou, is a province on the southern coast of mainland China. Located in the south of Nanling, on the coast of the South China Sea, it borders Hong Kong, Macau, Guangxi, Hunan, Jiangxi and Guangdong, and faces Hainan across the sea.
Since the Qin Dynasty, immigrants from the Central Plains have moved in continuously in Guangdong, gradually forming the three major ethnic groups of Cantonese, Hakka and Minnan, and forming a unique Lingnan culture. Cantonese, Hakka and Hokkien are commonly used in Guangdong, and the centers of Cantonese and Hakka dialects are both located in Guangdong. Guangdong is also currently the most populous province in China.
In the pre-Qin period, Guangdong had a high degree of civilization in the Neolithic Age and the Bronze Age, and was one of the birthplaces of Chinese civilization. Guangdong is the southern gate of China and is located in the shipping hub of the South China Sea. Since the Qin and Han dynasties, the people of Guangdong have embarked on the road of communicating with other parts of the world through the ocean, becoming the earliest birthplace of the Maritime Silk Road. After the reform and opening up, Guangdong has become a frontier position for reform and opening up and a window for the introduction of Western economy, culture and technology, and has achieved remarkable results.
2. How to download Google Earth elevation DEM data in Guangdong Province?
The offline data package of the Google Earth Elevation DEM contour line in Guangdong Province is 268.6MB, which can be downloaded directly from the Baidu network disk.
The download address is:
https://pan.baidu.com/s/1MIEw6VcVcNV6UZM4aJHNYA
The decompressed directory mainly includes the Guangdong Google Earth Elevation DEM Data.dat, the Guangdong Google Earth Elevation DEM Data.idx, and the Guangdong Google Earth Elevation DEM Data.kml files.
Double-click the shortcut of "Google Earth Elevation Data Reading and Exporting Tool" to download "Shuijingzhu Universal Map Downloader" for exporting elevation data as TIF files.
3. Administrative divisions of counties and cities included in the Google Earth elevation DEM data in Guangdong Province
The administrative division of Google Earth elevation DEM data in Guangdong Province mainly includes four regions: Pearl River Delta, East Guangdong, West Guangdong and North Guangdong, among which the Pearl River Delta: Guangzhou, Shenzhen, Foshan, Dongguan, Zhongshan, Zhuhai, Jiangmen, Zhaoqing, Huizhou; East Guangdong : Shantou, Chaozhou, Jieyang, Shanwei; Western Guangdong: Zhanjiang, Maoming, Yangjiang; Northern Guangdong: Shaoguan, Qingyuan, Yunfu, Meizhou, Heyuan.
How to export Google Earth elevation DEM data in Guangdong Province as TIF files?
After downloading and installing the universal map downloader and launching it, click "Task List" to open the download task list.
In the download task list, click the "Import" button to display the file selection dialog.
在文件选择对话框中，可以选择需要导入的“广东省谷歌地球高程DEM数据.dat”文件。
单击列表中的文件名称，可以查看所有图片的瓦片映射点，可以查看数据的完整性。有数据为绿色点，无数据为蓝色点，点击“查看结果”按钮可以预览查看高程DEM数据的渲染效果图。
移动鼠标到需要导出的影像名称上方，点击显示的“导出”按钮会显示“导出设置”对话框，可以将下载的广东省谷歌地球高程DEM数据拼接为大图，也可以导出为Cesium开源三维地球的高程DEM瓦片数据。
在将广东省谷歌地球高程DEM数据导出拼接为大图时，可以很方便地设置导出文件存储格式、坐标投影和设置背景透明等。同时，支持导出西安80、北京54和WGS84等多种平面坐标投影方式。
这里将坐标投影选择为“西安80高斯投影”、文件保存格式为“GeoTIF(*.tif)”、背景设置为透明，且勾选按边界范围剪裁等相关参数。设置完成之后，点击“确定”会导出下载结果。
需要将广东省谷歌地球高程DEM数据导出为CESIUM开源三维地球瓦片时，只需要选择“导出瓦片”功能项，然后选择瓦片格式为“高程CES瓦片”即可。
四、广东省谷歌地球高程DEM数据如何打开查看？
谷歌地球高程DEM数据需要在专业软件中才可以进行打开查看，如GlolbalMapper或ArcGIS等,这里以GlobalMapper为例。在导出结果目录中，将“广东省谷歌地球高程DEM数据.tif”文件拖放到GlobalMapper中即可打开，效果如下图所示。
广东省谷歌地球高程DEM数据局部放大之后，效果如下图所示。
五、广东省谷歌地球高程DEM数据如何提取10米等高线？
广东省谷歌地球高程DEM数据如何提取10米等高线的方法，请参阅官网教程：
六、结语
To sum up, the offline package of Google Earth elevation DEM data in Guangdong Province directly downloaded from Baidu's network disk can be exported as a TIF elevation file in Xi'an 80 or Beijing 54 coordinate system through the universal map downloader according to actual application requirements.
The TIF elevation DEM file exported by the universal map downloader can also be used to extract contour lines or generate 3D terrain through professional software such as GlobalMapper or ArcGIS, which is suitable for 3D simulation, 3D terrain modeling or construction of virtual 3D scenes and other applications.
For related documentation tutorials, see:
GlobalMapper cracked Chinese version download and install graphic tutorials