The extent of the Niagara Escarpment in New York, Ontario, Michigan, and Wisconsin (marked in red).

This map's source is here archive copy at the Wayback Machine, with the uploader's modifications, and the GMT homepage archive copy at the Wayback Machine says that the tools are released under the GNU General Public License.

originally uploaded to the English Wikipedia, as en:Image:Niagara Escarpment in Red.png. history there:

(del) (cur) 17:20, 22 December 2005 . . Kelisi (Talk | contribs) . . 931×535 (29,293 bytes) (The extent of the Niagara Escarpment in New York, Ontario, Michigan, and Wisconsin (marked in red). This map's source is [http://www.aquarius.geomar.de/omc/make_map.html here], with the uploader's modifications, and the [http://gmt.soest.hawaii.edu/ GMT ) NOTE: The links to the map's source and the uploader's modifications are both dead as of December 1, 2019. Sciencebookworm (留言) 05:43, 1 December 2019 (UTC)

	本文件采用知识共享署名-相同方式共享 3.0 未本地化版本许可协议授权。 受免責聲明的約束。
	您可以自由地： 共享 – 复制、发行并传播本作品 修改 – 改编作品 惟须遵守下列条件： 署名 – 您必须对作品进行署名，提供授权条款的链接，并说明是否对原始内容进行了更改。您可以用任何合理的方式来署名，但不得以任何方式表明许可人认可您或您的使用。 相同方式共享 – 如果您再混合、转换或者基于本作品进行创作，您必须以与原先许可协议相同或相兼容的许可协议分发您贡献的作品。
	本许可协议标签作为GFDL许可协议更新的组成部分被添加至本文件。http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue

已授权您依据自由软件基金会发行的无固定段落及封面封底文字（Invariant Sections, Front-Cover Texts, and Back-Cover Texts）的GNU自由文件许可协议1.2版或任意后续版本的条款，复制、传播和／或修改本文件。该协议的副本请见“GNU Free Documentation License”。 受免責聲明的約束。http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue