JSON annotation format

The ​JSON format for annotations is based on the ​Annotator Store API.

Image areas

Annotations of image areas have a "shapes" member, specifying a list of shapes on the image. The shape definitions are based on the ​SVG shape definitions.

The possible shape forms are

• point
• rectangle
• polygon (not yet implemented)
• circle (not yet implemented)

Coordinates and coordinate units are specified in a "geometry" member.

The coordinate unit "fraction" means that each coordinate is specified as a decimal fraction (float 0 <= x <= 1) of the image side length, e.g. x=0.03 means that x is at 3% of the total image width.

Example of an image area specification:

"shapes" : [{
  "type" : "rectangle",
  "geometry" : {
    "units" : "fraction",
    "x" : 0.0123,
    "y": 0.345,
    "width" : 0.567,
    "height": 0.789
  }
}]