貯水池の流域

Question

<\/HEAD>こんにちは、<\/P> <\/P> 私はwatershedツールの使用は初心者です。ストリームゲージの位置などのためにpour pointsを使用および作成できることはわかっていますが、もし私がポイントではなくポリゴンである高地の池の流域を見つけようとしている場合はどうすればよいでしょうか...池の沿岸にpour pointを見つけるべきでしょうか、それとも池のポリゴン領域を使って流域を見つける方法はありますか？それから二次的な質問ですが、DEMでfillを行うと私の貯水池は埋まりますか？<\/P> <\/P> ありがとうございます、<\/P> <\/P> Jessica <\/P><\/BODY><\/HTML>

GabrielUpchurch1 · Answer

For the pour points, I would test Sephe's suggestion first to see what you get but I suspect you may get watersheds for each cell in the pond.  I haven't tested this approach so it would be beneficial for you to try it.  Even if you get a bunch of small watersheds, you could post process the data into a single watershed for the whole pond.  Alternatively, if the pond has an outlet, dam, levee, spillway, etc., you could place a point there or if all land around the pond drains into the pond, you could use the pond's centroid.  General knowledge of the slope of the terrain and hydrology for the area will play into where you place a point.

As Sephe pointed out, you will need to experiment with the z limit parameter to avoid having your pond filled.

SepheFox · Answer

Hi Jessica, to answer your second question, you can set a z limit for your fill, such that it won't fill your pond. You can try to figure out what that is, or just play around with the z limit until you fill surrounding sinks, but not your pond. As far as the pour point, you might try converting your pond polygon to a raster, so that all the cells of the pond will be used to find the contributing watershed area.