useful 3D software

I'll continue to write about the Kanda river.

I have a 3D map software in my computer.

It can describe an undulation on a land from

calculation from a altitude date.

I'll try to compare between the real photos and

the generated 3D photos. 

Photo 1. The real scene:
There are a hill there, and the Kanda river penetrates
the hill.

Photo 2. Close to the river.
You can see big walls laid at both shores.

Photo 3. the generated 3D photo
The center blue line shows the Kanda river.
The upper side oｆ this photo is the downstream direction.
The green area is lower altitude than the brawn area.
The Kanda river goes through the hill, it appears unnatural
because it would be easy to follow to turn left, going to lower land.