.. meta::
   :description: Documentation of the coordinates system of the bounding boxes used in Konfuzio and some simple 
examples of how to use it for visualization, for example.

## Coordinates System

The size of a page of a Document can be obtained in the Document object.
The format is [width, height].

Original size of the Document is the size of the uploaded Document (which can be a PDF file or an image). The bounding 
boxes of the Annotations are based on this size.
   E.g.: [1552, 1932]


Current size can be accessed via calling `height` and `width` from the Page object. They show the dimensions of the 
image representation of a Document Page. These representations are used for computer vision tasks and the SmartView.
   E.g.: [372.48, 463.68]

.. literalinclude:: /sdk/boilerplates/test_coordinates_system.py
   :language: python
   :start-after: Start coordinates
   :end-before: End coordinates
   :dedent: 4


The coordinates system used has its start in the bottom left corner of the page.

.. image:: /_static/img/coordinates_schema.png


To visualize the character bounding boxes of a document and overlapping them in the image opened with the python
library PIL, for example, we can resize the image to the size in which they are based (original_size).
The following code can be used for this:

.. literalinclude:: /sdk/boilerplates/test_segmentation_and_bboxes.py
   :language: python
   :start-after: start document
   :end-before: end document
   :dedent: 4

.. image:: /_static/img/bboxes_characters.png

The coordinates obtained from the segmentation endpoint of the API are based on the image array shape.
To visualize the segmentation bounding boxes of a page on an image opened with the python library PIL, for example,
we can overlap them directly.

.. literalinclude:: /sdk/boilerplates/test_segmentation_and_bboxes.py
   :language: python
   :start-after: start segmentation
   :end-before: end segmentation
   :dedent: 4

.. image:: /_static/img/bboxes_segmentation.png

To visualize both at the same time we can convert the coordinates from the segmentation result to be based on the image
size used for the characters' bbox.

.. literalinclude:: /sdk/boilerplates/test_segmentation_and_bboxes.py
   :language: python
   :start-after: start dimensions
   :end-before: end dimensions
   :dedent: 4

.. image:: /_static/img/bboxes_overlap.png