# Reprocessing step 1 with existing MTPs/GCPs

**URL:** <https://community.pix4d.com/t/reprocessing-step-1-with-existing-mtps-gcps/18958>\
**Category:** PIX4Dmapper\
**Created:** [July 13, 2021, 6:16am UTC](https://community.pix4d.com/t/reprocessing-step-1-with-existing-mtps-gcps/18958 "2021-07-13T06:16:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![till](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/till/32/3151_2.png) [@till](https://community.pix4d.com/u/till)\
**Post date:** [July 13, 2021, 6:16am UTC](https://community.pix4d.com/t/reprocessing-step-1-with-existing-mtps-gcps/18958/1 "2021-07-13T06:16:02Z")

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How exactly does pix4d deal with MTPs and GCPs if step 1. Initial Processing is recalculated with different settings, altough MTPs and GCPs already exist from a previous calculation of step 1? The points where marked via raycloud and basic editor.

It’s obvious that regarding the processing of step 1. Initial Processing MTPs/GCPs remain in the project, but are they included comprehensively in the calculation itself?

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**Author:** ![Yuka](https://avatars.discourse-cdn.com/v4/letter/y/9d8465/32.png) [@Yuka](https://community.pix4d.com/u/Yuka)\
**Post date:** [July 14, 2021, 6:49am UTC](https://community.pix4d.com/t/reprocessing-step-1-with-existing-mtps-gcps/18958/2 "2021-07-14T06:49:01Z")

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If the GCPs are marked on the images, they should be included in the calculation; however, I recommend checking the marked images after step 1 to see if GCPs are marked at the right place just in case.

Kind regards,