Definitions of improved:

• adjective:   made more desirable or valuable or profitable; especially made ready for use or marketing

  Example: "New houses are springing up on an improved tract of land near the river"

• adjective:   (of land) made ready for development or agriculture by clearing of trees and brush

  Example: "Improved farmlands"

• adjective:   become or made better in quality

  Example: "Was proud of his improved grades"