高程数据下载——DLR_SRTM_说明

翻译DLR文档

DLR SRTM X-SAR Digital Elevation Models

 

 

The German Aerospace Center DLR is making the SRTM X-SAR digital elevation models (DEMs) available at no cost. The data can be accessed in three ways

 

• Traditional search and ordering via the DLR Earth Observation data portal EOWEB-NG,
• FTP bulk download via EOWEB-NG
• Viewing (WMS) and download (WCS/WFS) via the EOC Geoservice

 

This document contains background information on the mission and the DEM products, on data access and data use. More detailed information can be obtained by following the links provided.

 

 

The Shuttle Radar Topography Mission - SRTM

 

The SRTM X-SAR DEMs were generated from X-band synthetic aperture radar (SAR) data acquired during the Shuttle Radar Topography Mission (SRTM) in 2000. The SRTM mission was conducted jointly between the German Aerospace Center DLR, the Italian Space Agency ASI, and NASA/JPL (USA). From February 11 to 22, 2000, two interferometric radar systems onboard the Space Shuttle Endeavor acquired data with the objective to generate a global high resolution digital elevation model. The American radar system, operating in C-band, was complemented by the German-Italian X-SAR, a higher resolution X- band synthetic aperture radar (SAR) system.

 

The SRTM DEMs were generated using 'radar interferometry' or 'InSAR'. Two SAR antennas, one inside the Space Shuttle cargo bay, the other at the end of a 60 m extension pole, simultaneously acquired radar data. During the processing, the phase differences of the two corresponding datasets are compared and converted into elevation values. An introduction to SAR interferometry can be found at this site.

 

The DLR SRTM website provides additional information on the SRTM X-SAR mission. Further details on the SRTM mission, on technology, accuracies, and applications are available on the NASA SRTM website and in this document.

 

While the DEMs generated from the American C-band data are available through the United States Geological Survey USGS and other sites, the X-SAR DEMs can be obtained via DLR.

 

 

DLR SRTM X-SAR数字高程模型

 

 

德国航空航天中心DLR正在免费提供SRTM X-SAR数字高程模型（DEM）。可以通过三种方式访问​​数据

 

•通过DLR地球观测数据门户网站EOWEB-NG进行传统搜索和订购，

•通过EOWEB-NG进行FTP批量下载

•通过EOC Geoservice查看（WMS）和下载（WCS / WFS）

 

本文档包含有关任务和DEM产品的背景信息，包括数据访问和数据使用。可以通过提供的链接获得更详细的信息。

 

 

航天飞机雷达地形任务 - SRTM

 

SRTM X-SAR DEM是在2000年航天飞机雷达地形任务（SRTM）期间获得的X波段合成孔径雷达（SAR）数据生成的.SRTM任务由德国航空航天中心DLR，意大利航天局ASI联合进行。和NASA / JPL（美国）。 2000年2月11日至22日，奋进号航天飞机上的两个干涉雷达系统获得了数据，目的是生成全球高分辨率数字高程模型。在C波段运行的美国雷达系统由德国 - 意大利X-SAR补充，这是一种更高分辨率的X波段合成孔径雷达（SAR）系统。

 

SRTM DEM使用“雷达干涉测量”或“InSAR”生成。两个SAR天线，一个位于航天飞机货舱内，另一个位于60米延伸杆末端，同时获取雷达数据。在处理期间，比较两个相应数据集的相位差并将其转换为高程值。可在此站点找到SAR干涉测量的介绍。

 

DLR SRTM网站提供有关SRTM X-SAR任务的更多信息。有关SRTM任务，技术，准确性和应用的更多详细信息，请访问NASA SRTM网站和本文档。

 

虽然美国C波段数据生成的DEM可通过美国地质调查局USGS和其他站点获得，但X-SAR DEM可通过DLR获得。

 

 

 

Coverage

 

Similar to the NASA/JPL SRTM C-band data, the DLR/ASI X-SAR DEMs cover the entire globe between 60° northern and southern latitude. However, the coverage of the X-band DEMs is not continuous. The gaps between the individual crisscrossing image strips are a result of the higher precision and therefore a narrow swath width of the X-band system. Information on the precise coverage of the SRTM X-SAR data can be obtained from the DLR SRTM website.

 

 

覆盖

 

与NASA / JPL SRTM C波段数据类似，DLR / ASI X-SAR DEM覆盖全球60°北纬和南纬之间。 但是，X波段DEM的覆盖范围并不是连续的。 各个交叉图像条之间的间隙是更高精度的结果，因此X波段系统的窄条带宽度。 有关SRTM X-SAR数据精确覆盖的信息可以从DLR SRTM网站获得。

 

Accessing SRTM X-SAR DEMs

 

Since December 2010 the DLR SRTM X-SAR DEMs are available at no cost. The data can be obtained via EOWEB-NG (http://eoweb.dlr.de), the Earth observation data portal of the Earth Observation Center at DLR. A user can perform a traditional search for SRTM data in EOWEB-NG and order up to 100 datasets. Additionally, the SRTM X-band DEMs can be downloaded in bulk from an FTP-Server, accessible via a separate link after logging on to EOWEB-NG. The EOC Geoservice provides a third way of accessing the SRTM X-SAR data via technical interfaces compliant with the standards of the Open Geospatial Consortium OGC. The OGC-compliant services include data discovery (CSW), viewing (WMS), and download (WCS/WFS) and are accessible via geoservice.dlr.de.

 

SRTM X-SAR DEMs via FTP-Download

 

Via FTP-download the SRTM X-SAR DEMs are provided as compressed archives. One archive contains individual digital elevation models (DEMs) covering a geographic area of 10° by 10°. The filename of the archive specifies the bottom left coordinate of the 10° by 10° tile. In addition to the DEM files, the archive contains the corresponding height error maps (HEM), a browse image map providing an overview of the area covered by the files contained in the archive, a kml file for displaying the browse image of the coverage on Google Earth, and this 'Readme' file.

 

The corresponding SAR image data are not included in the package. They can, however, be ordered via EOWEB-NG (http://eoweb.dlr.de).

 

访问SRTM X-SAR DEM

 

自2010年12月起，DLR SRTM X-SAR DEM可免费提供。数据可以通过DLR地球观测中心的地球观测数据门户EOWEB-NG（http://eoweb.dlr.de）获得。用户可以在EOWEB-NG中对SRTM数据执行传统搜索，并订购多达100个数据集。此外，SRTM X波段DEM可以从FTP服务器批量下载，登录到EOWEB-NG后可通过单独的链接访问。 EOC Geoservice提供了第三种通过符合开放地理空间联盟OGC标准的技术接口访问SRTM X-SAR数据的方法。符合OGC标准的服务包括数据发现（CSW），查看（WMS）和下载（WCS / WFS），可通过geoservice.dlr.de访问。

 

SRTM X-SAR DEM通过FTP下载

 

通过FTP下载，SRTM X-SAR DEM以压缩档案的形式提供。一个档案包含覆盖10°到10°地理区域的单个数字高程模型（DEM）。存档的文件名指定10°×10°图块的左下角坐标。除了DEM文件之外，存档还包含相应的高度错误映射（HEM），一个浏览图像映射，提供归档中包含的文件所覆盖区域的概述，一个用于显示覆盖率的浏览图像的kml文件。谷歌地球和这个'自述'文件。

 

相应的SAR图像数据不包括在包中。但是，它们可以通过EOWEB-NG（http://eoweb.dlr.de）订购。

 

Details on DEMs and Data Format

 

The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile.

 

The DEM and HEM data are in geographic (Lat/Long) projection, with datum WGS84. The elevation  values are also WGS84, as specified in the product description available from the DLR SRTM website.

 

One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.)   /

±15 m (rel.), both 90% circular error. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% linear error. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file.

 

As a result of the processing methodology a few locations within the DEM will have no data values. These voids have not been removed in this particular product. Standard Remote Sensing image processing tools, however, are able to compute and insert the missing values. The DEMs have not been edited with respect to coastlines and water bodies. Therefore, coastlines may not be well defined and water bodies may not be perfectly flat.

 

The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at the DLR SRTM website.

 

Since the DLR SRTM X-SAR DEMs are an experimental product they are provided as is on a best effort basis.

 

有关DEM和数据格式的详细信息

 

压缩归档内的DEM作为单独的文件分发，即它们不镶嵌到一个大的DEM文件中。每个DEM占地面积为15'乘15'。单个DEM文件的文件名指定相应的15英尺×15英尺DEM图块的左下坐标。

 

DEM和HEM数据采用地理（纬度/长度）投影，数据为WGS84。高程值也是WGS84，如DLR SRTM网站提供的产品说明中所述。

 

DEM文件的一个像素对应于地面上大约25米×25米。高程值以1米的分辨率提供。 SRTM X波段DEM的水平精度为±20 m（绝对）/

±15米（相对），均为90％圆形误差。垂直精度为±16 m（绝对）/±6 m（相对），均为90％线性误差。有关单个图块的垂直和水平精度的精确信息可以在DTED文件的精度描述记录（ACC）中找到。

 

作为处理方法的结果，DEM内的一些位置将没有数据值。这种特殊产品中没有去除这些空隙。但是，标准遥感图像处理工具能够计算和插入缺失值。关于海岸线和水体的DEM尚未编辑。因此，海岸线可能没有明确定义，水体可能不是完全平坦的。

 

X波段SRTM DEM数据以DTED格式提供。有关DTED格式的详细信息，请参阅DLR SRTM网站上的“SRTM DTED格式的产品描述”（SRTM / PD-03/11/03）。

 

由于DLR SRTM X-SAR DEM是一种实验性产品，因此它们是在尽力而为的基础上提供的。

 

 

Conditions of Use

 

The use of the SRTM data is governed by the following conditions of use. By clicking on the button 'Download SRTM data' or by accessing the data via the FTP-link provided, you are accepting these conditions of use.

 

The SRTM DEM data are intended primarily for scientific purposes. Redistribution of the original SRTM data is not permitted, neither for commercial nor for non-commercial purposes. No further restrictions, except for those contained herein, are being imposed on the use of the data or derived products.

 

The SRTM-X band DEMs have been processed to the highest possible standards of accuracy using state- of-the-art technology. However, the data are provided as is. No warranty of any kind, whether explicit or implied is given. Furthermore, as the SRTM data are provided free-of-charge, DLR shall not be liable for any damage arising out of the SRTM data’s use. The user is responsible for observing that no damage is caused to anyone or anything by his use of the SRTM data. By clicking on the button 'Download SRTM data' or by accessing the data via the FTP-link provided, the user therefore agrees to hold the German Aerospace Center (DLR) harmless from and against any and all claims which might arise by himself or  any third party out of the SRTM data’s use.

 

For all products based on the SRTM X-band data, and for all publications including these data or derived products, it is mandatory to use the following copyright information: ©DLR/ASI .

 

使用条件

 

SRTM数据的使用受以下使用条件的约束。通过单击“下载SRTM数据”按钮或通过提供的FTP链接访问数据，即表示您接受这些使用条件。

 

SRTM DEM数据主要用于科学目的。不允许重新分发原始SRTM数据，无论是出于商业目的还是出于非商业目的。除了此处包含的限制外，不对数据或衍生产品的使用施加进一步的限制。

 

SRTM-X频段DEM采用最先进的技术，以最高的精度标准进行处理。但是，数据按原样提供。不作任何明示或暗示的保证。此外，由于SRTM数据是免费提供的，因此DLR对SRTM数据使用造成的任何损害不承担任何责任。用户有责任观察他使用SRTM数据对任何人或任何事物造成的损害。通过点击“下载SRTM数据”按钮或通过提供的FTP链接访问数据，用户因此同意让德国航空航天中心（DLR）免受任何和所有可能由他自己或任何人提出的索赔的损害。 SRTM数据使用中的第三方。

 

对于基于SRTM X波段数据的所有产品，以及包括这些数据或衍生产品在内的所有出版物，必须使用以下版权信息：©DLR / ASI <生产年份>。