Tiled is a general purpose tile map editor. It's built to be easy
to use, yet flexible enough to work with varying game engines,
whether your game is an RPG, platformer or Breakout clone. Tiled
is free software and written in C++, using the Qt application
framework. The main features in a nutshell:

 * General purpose tile map editor with XML-based map format
 * Supports orthogonal and isometric maps
 * Custom objects can be placed with pixel precision
 * Full undo/redo and copy/paste support
 * Add custom properties to tiles, layers, objects or the map
 * Automatically reloads tilesets when changed externally
 * Resize or offset your tile map later as needed
 * Efficient tile editing tools like stamp and fill brushes
 * Supports input/output plugins to open and save files in custom
   formats

WWW: https://www.mapeditor.org/