Annotating a specific point of an image

Use Case

You want to annotate a coordinate of the image rather than a region. You have a map with some locations that can be represented better by a single coordinate. You want to add some auxiliary data relative to a specific point of the image (e.g. some spectroscopic analysis made on a manuscript).

Implementation notes

This recipe, as Simple Annotation — Tagging implements a method for annotating an image. Recipe Begin playback at a specific point - Time-based media uses a Point Selector for selecting a specific time of a video, this recipe selects instead a specific point of the image.

In this use case, the Annotation is inside an Annotation Page in the annotations list of the Manifest. The motivation of the Annotation is “tagging” and the target source points to the Canvas id. The type property is a Specific Resource while the Selector type property is a Point Selector that contains the coordinates x and y of the Canvas coordinates system as parameters.

Viewers might consider implementing scale-independent point markers so that they are visible at every level of zoom.


This example uses a leaflet with a map and a guide supplied by the Library of Congress Geography and Map Division, it shows how we can annotate some locations expressed in the map.


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