# Marking GCPs from arbirary grid

**URL:** <https://community.pix4d.com/t/marking-gcps-from-arbirary-grid/27884>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [September 28, 2023, 2:49pm UTC](https://community.pix4d.com/t/marking-gcps-from-arbirary-grid/27884 "2023-09-28T14:49:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![doug.macfarland](https://avatars.discourse-cdn.com/v4/letter/d/85e7bf/32.png) [@doug.macfarland](https://community.pix4d.com/u/doug.macfarland)\
**Post date:** [September 28, 2023, 2:49pm UTC](https://community.pix4d.com/t/marking-gcps-from-arbirary-grid/27884/1 "2023-09-28T14:49:01Z")

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We are provided GCPs in an arbitrary local grid on construction sites. Our drone is the DJI M300 RTK so the images are geolocated. I’m trying to figure out the best process for adding and marking the GCPs. Do I run the step 1 then import the GCPs and mark them in ray cloud? Or do I add the GCPs prior to step 1? When would I use the Basic method for marking?

Thank You

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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:** [October 2, 2023, 11:01pm UTC](https://community.pix4d.com/t/marking-gcps-from-arbirary-grid/27884/2 "2023-10-02T23:01:07Z")

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Hi Doug,

You will have to use the Basic GCP editor. This is because Mapper does not know how to display arbitrary coordinates. You can mark your GCPs before step 1.

> **[How to add / import GCPs using the Basic GCP/MTP Editor - PIX4Dmapper](https://support.pix4d.com/hc/en-us/articles/202560099-How-to-add-import-GCPs-using-the-Basic-GCP-MTP-Editor-PIX4Dmapper)**
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> This article explains how to add and import ground control points (GCPs) when using the Basic GCP/MTP Editor. 
> 
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> Important:
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> These step-by-step instructions are part of the procedure of how to inc...