Different scenario causes cropping error

[matthewma7]

The cropping for vector and raster data works for general cases. But there is some scenario will cause errors.

• Raster data
  • Crop region is bigger than the target
  • Crop region is entirely outside the target area
  • Some maybe special RGB datsaet will lose color in the cropped result
• Vector data
  • Crop region is entirely outside the target area

I uploaded some example data here for these cases.

[johnkit]

@matthewma7

• I cannot duplicate the "lose color" issue. Maybe we can look at that in the coming week.
• As for the other problems, I think that PR #127 fixes them. Do you want to review that before I merge?

[johnkit]

Resolve by PR #127