# Processing Workflow with GCPs and Project to be on a Custom CRS

**URL:** <https://community.pix4d.com/t/processing-workflow-with-gcps-and-project-to-be-on-a-custom-crs/34538>\
**Category:** PIX4D International\
**Created:** [May 13, 2026, 6:15pm UTC](https://community.pix4d.com/t/processing-workflow-with-gcps-and-project-to-be-on-a-custom-crs/34538 "2026-05-13T18:15:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![allan](https://avatars.discourse-cdn.com/v4/letter/a/ccd318/32.png) [@allan](https://community.pix4d.com/u/allan)\
**Post date:** [May 13, 2026, 6:15pm UTC](https://community.pix4d.com/t/processing-workflow-with-gcps-and-project-to-be-on-a-custom-crs/34538/1 "2026-05-13T18:15:09Z")

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Can I please get some advice on the best workflow step by step when processing a aerial dataset with GCPs on a Custom CRS

Using PIX4dMaticPRO

AGLIME94

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**Author:** ![Mike\_K](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/mike_k/32/4697_2.png) [@Mike\_K](https://community.pix4d.com/u/Mike_K)\
**Post date:** [June 24, 2026, 4:13pm UTC](https://community.pix4d.com/t/processing-workflow-with-gcps-and-project-to-be-on-a-custom-crs/34538/2 "2026-06-24T16:13:27Z")

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Hi Allan,

Processing with an arbitrary coordinate system is generally the same as working with a known coordinate system. The main difference is that PIX4Dmatic cannot automatically locate the images, since their positions relative to the GCPs are unknown. As a result, you will need to manually browse through the dataset to identify the corresponding images, which can be time-consuming and increases the risk of errors.

To help with this, we recently released an online Site Localization Calculator. If you have a table of GCPs defined in both a local and a known/global coordinate system, the calculator can generate a file that automatically geolocates your project. This can significantly speed up project setup and help ensure that GCPs are marked correctly.

You can read more about the site localization calculator in our support article:

> **[Site localization calculator](https://support.pix4d.com/hc/how-to-obtain-a-site-localization-file-for-pix4dmatic-and-pix4dcloud)**
>
> Site localization converts global GNSS coordinates into a local coordinate system using a WKT file. To obtain this file, follow the steps outlined in this article.