# Relationship between injection coordinates in data portal and sdk

**URL:** <https://community.brain-map.org/t/relationship-between-injection-coordinates-in-data-portal-and-sdk/436>\
**Category:** Technical\
**Tags:** reference-coordinates, atlas-mouse-brain-connectivity, how-to, allensdk\
**Created:** [February 6, 2020, 5:26pm UTC](https://community.brain-map.org/t/relationship-between-injection-coordinates-in-data-portal-and-sdk/436 "2020-02-06T17:26:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![robertooooo](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/robertooooo/32/243_2.png) [@robertooooo](https://community.brain-map.org/u/robertooooo)\
**Post date:** [February 6, 2020, 5:26pm UTC](https://community.brain-map.org/t/relationship-between-injection-coordinates-in-data-portal-and-sdk/436/1 "2020-02-06T17:26:39Z")

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Hi,

The injection coordinate in the data portal (e.g.:[https://connectivity.brain-map.org/projection/experiment/113226232](https://connectivity.brain-map.org/projection/experiment/113226232)) is in mm and relative to Bregma while the data downloaded using allensdk.core.mouse\_connectivity\_cache.MouseConnectivityCache.get\_structure\_unionizes are using a different coordinate system. How do I convert bregma coordinates to the sdk system? What is the bregma coordinate in the reference atlas?

Thanks!

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**Author:** ![robertooooo](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/robertooooo/32/243_2.png) [@robertooooo](https://community.brain-map.org/u/robertooooo)\
**Post date:** [February 7, 2020, 10:46am UTC](https://community.brain-map.org/t/relationship-between-injection-coordinates-in-data-portal-and-sdk/436/2 "2020-02-07T10:46:47Z")

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I just realized I can get the coordinates of the injection looking at the annotation where the field “is\_injection” is equal 1. Should have thought about it!

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**Author:** ![amyb](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/amyb/32/32_2.png) [@amyb](https://community.brain-map.org/u/amyb)\
**Post date:** [February 7, 2020, 4:47pm UTC](https://community.brain-map.org/t/relationship-between-injection-coordinates-in-data-portal-and-sdk/436/3 "2020-02-07T16:47:25Z")

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Hi @robertooooo,

Thanks for posting, and glad you found the solution. You also might be interested in reading a previous post about Bregma:

> [@Why doesn't the 3D Mouse Brain Atlas have Bregma coordinates?](https://community.brain-map.org/t/why-doesnt-the-3d-mouse-brain-atlas-have-bregma-coordinates/158):
>
> “Where can I find Bregma?” We get this question frequently from researchers who are using the [Allen Mouse Brain Adult Reference Atlas](http://atlas.brain-map.org/) in the Common Coordinate Framework (CCF), which can be viewed in the [Allen Brain Explorer](http://connectivity.brain-map.org/3d-viewer). Bregma is the area of the mammalian skull where the sagittal and coronal sutures joining the parietal and frontal bones come together. If you understand how the reference atlas and CCF were created, it will make sense why there are no Bregma coordinates shown in the web b…