# Layers disappear when GCP added

**URL:** <https://community.pix4d.com/t/layers-disappear-when-gcp-added/21988>\
**Category:** PIX4Dmapper\
**Created:** [March 27, 2022, 1:57pm UTC](https://community.pix4d.com/t/layers-disappear-when-gcp-added/21988 "2022-03-27T13:57:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![joe.stroup](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/joe.stroup/32/5290_2.png) [@joe.stroup](https://community.pix4d.com/u/joe.stroup)\
**Post date:** [March 27, 2022, 1:57pm UTC](https://community.pix4d.com/t/layers-disappear-when-gcp-added/21988/1 "2022-03-27T13:57:39Z")

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Hello - and thank you for helping me!

I’m a new user, and learning Pix4D with a trial license. I hope to buy the license.

I’ve had good luck with Pix4D-Mapper making photomosaics and 3-D meshes using my drones capturing up to 750 images over 40 acres. I’m very pleased.

I started to learn how to include GCP’s, and I’ve run into a problem.

When I include my first GCP and re-run Step-1, all the cameras disappear from view.

I thought perhaps I had a problem with a mismatch of coordinate systems.

I discovered that Pix4D auto-detected the UTM Zone “17N” for my photos. My project is in UTM Zone “17S”. I started from the beginning again, and set the output coordinate system to UTM Zone “17S” - and re-created the project - and ran Step-1 again. Then I added a GCP, and set it’s coordinates to UTM Zone “17S” as well.

Then - re-running Step-1, all the cameras disappear from the view.

I’ve included screen-shots that may help explain. I’ve also included a screen shot of a map that shows that my subject location is in-fact in UTM Zone 17S.

Please let me know if I can provide more information.

Thank you for helping me!

 ![With no GCP's - layers viewable](https://global.discourse-cdn.com/pix4d/original/2X/c/c071580a4f13f4a499b38b1eb8a95bf97c8cd799.png)

 ![With GCP - blank layers](https://global.discourse-cdn.com/pix4d/original/2X/6/659cde75d6c999840dfe519be0d357e49d213a31.png)

 ![output coordinate system](https://global.discourse-cdn.com/pix4d/original/2X/2/249b9f95d4d5e3faffc7a7c4a1dcf39749530080.png)

 ![coordinates converter - showing tribble mill park](https://global.discourse-cdn.com/pix4d/original/2X/8/8b877b848a62d7f75c1c170802515feca145dbdc.png)

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<div class="post-metadata">

**Author:** ![joe.stroup](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/joe.stroup/32/5290_2.png) [@joe.stroup](https://community.pix4d.com/u/joe.stroup)\
**Post date:** [March 28, 2022, 2:21pm UTC](https://community.pix4d.com/t/layers-disappear-when-gcp-added/21988/3 "2022-03-28T14:21:16Z")

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PROBLEM RESOLVED

I discovered that Pix4D was expecting UTM coordinates for my GCP’s. I’d been using decimal degrees.