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全球地区低于海平面数据集?

谁知道地区低于海平面的现有数据集?向量区段将是理想的。不需要非常详细的为我的目的,但是它会好如果包括所有领域(例如高估比低估)。

有一个列表的地方在陆地上维基百科上海拔低于海平面,这看起来很完整,但发现海平面以下区域每一个区段的位置不可能是简单的。

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你可以尝试构建一个使用全球数字高程模型。有几个免费的像图像中[1],[SRTM][2],或[ASTER GDEM] [3]。你要寻找的所有像素包含一个负值。邻-像素会给你连接地区低于海平面,你可以很容易地估计他们仅仅通过区域的像素的数量乘以一个像素的面积。我不是说这很容易。一些地区的主要挑战可能会将跨越几个瓷砖。_____________________________________________更新。我花了几个小时在这作为练习。我下载三个瓷砖从ASTER全球DEM围绕Badwater盆地(美国死亡谷),维基百科的一个地区列表。我写了一个小(~ 20行)Matlab脚本如下:-二值化的图像,每个像素海拔高度设置为0(黑色)和每个像素低于海平面设置为1(白色)。 - Concatenation of the three arrays in order to have only one image for the next step (I manually added a fourth, all black array for the sake of dimension consistency). - With a binary image, Matlab has a useful function called `regionprops` that finds all connected regions and returns their properties, such as their area (as a number of pixel). Here is the result: [![Badland_Basin_black_and_white][4]][4] I'm pretty happy with it, as it looks very similar to the yellow area labelled "below sea level" on [this USGS map][5]. [![enter image description here][6]][6] Now, how does it translate in terms of area? According to Matlab, the white region has an area of 1 236 989 pixels. Each pixel being approximately 30x30 meters, it yields a below sea level area of 1 113 km$^2$. The only figure I could find online is [1 425 km$^2$][7] from Encyclopedia Britannica, with no source. But for me that's close enough to have confidence in my estimate! Some shortcomings: - I knew exactly which tiles contained this particular below sea level region. If you were to go through all tiles (almost 23 000!), you'd have to figure a way to detect when a region is split across multiple tiles in order to reconstruct the region by concatenation. Doesn't seem that hard, but not trivial. - I did not take into account the fact that there is a one pixel overlap between adjacent tiles (it should not change change the result much). - I did not take into account the fact that pixel size actually vary (the resolution is one arc second, which is ~30 meters at the equator but changes with latitude). [1]: https://geoservice.dlr.de/web/dataguide/tdm90/ [2]: https://www2.jpl.nasa.gov/srtm/ [3]: https://lpdaac.usgs.gov/news/nasa-and-meti-release-aster-global-dem-version-3/ [4]: https://i.stack.imgur.com/Xbo04.png [5]: https://web.archive.org/web/20071224063142/http://geology.wr.usgs.gov/parks/deva/ftbad2.html [6]: https://i.stack.imgur.com/G9iwo.gif [7]: https://www.britannica.com/place/Death-Valley

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\ begingroup美元是的,这似乎相当直接,结合上面的wiki列表中,全球可能是可行的。我想我最终可能不得不这样做,但是我虽然会值得问一些已经存在。 \ endgroup美元
- - - - - -naught101
2020年1月17日23:32
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\ begingroup美元如果你这样做,请在这里分享一个自我回答!:) \ endgroup美元
- - - - - -让-玛丽•Prival
,2020年1月18日

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