- Layers in a Plot:
  - A layer is a data set rendered on a plot.
  - There can be many layers on one plot.
  - Layers can:
    - Be Enabled/Disabled
    - Be Added/Removed
    - Have their characteristics (or attributes) changed
  - A layer may constitute a set of homogenous points.
    - For example: The midas file `cities.prm` contains a number of lat/lon points with city names.
  - The elements within a layer tend to have a number of attributes, like color, in common.
  - NeXtMidas has a number of classes for handling layers, here are just a few:

    Layer Class | Description
    --- | ---
    `Layer1D` | For Type 1000 Midas Blue files (`TYPE=Line`)
    `Layer2D` | For Type 2000 Midas Blue files (`TYPE=Raster`)
    `LayerGeo` | For geolocation related information
    `LayerImage` | For image files: gif,jpeg
    `LayerMulti` | For Type 3000 Midas Blue files with multiple Y traces
    `LayerPoly` | For Type 1999 Midas Blue files (e.g. `world.prm`)
    `LayerShape` | For shape (`.shp`) files
    `LayerT5` | For special Type 5000 Midas Blue files
    `LayerXY` | For Type 3000 Midas Blue files (scatter plots)

  - You can even add you own layers if you like. See the `LAYER` explain file for details.
  - See `LAYER` explain file for a complete list of layers.

X-Midas Users Take Note:
`LayerGeo` and `LayerT5` perform many of the functions embedded into the X-Midas `XGEOPLOT` command.