Create plane with lines?

I am very new to Sketchup. I’ve imported a model from Rhino in and my topo curves that I used to create a plane in Rhino are coming in as lines in sketchup. Basically I have a topographic surface, and I would like to have it be nice and clean as one surface instead of a combination of them. Is there a way to select the boundary curves or something on this complex surface and have sketchup delete the lines but maintain the surface? When I deleted one of the lines it disconnects the planes…

You need to show us what you are working with. Uploading the Sketchup file would be a big help. I am guessing you need to soften edges but it’s hard to say with so little information. SketchUp requires edges to create faces. If you erase an edge that is required for the face to exist, the face will go away, too. Softening edges will help to give the appearance of a continuous surface.