# Help with tieing imported points to photos for reoptimization.

**URL:** <https://community.pix4d.com/t/help-with-tieing-imported-points-to-photos-for-reoptimization/6940>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [July 25, 2018, 3:16pm UTC](https://community.pix4d.com/t/help-with-tieing-imported-points-to-photos-for-reoptimization/6940 "2018-07-25T15:16:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Blair\_Prigge](https://avatars.discourse-cdn.com/v4/letter/b/f05b48/32.png) [@Blair\_Prigge](https://community.pix4d.com/u/Blair_Prigge)\
**Post date:** [July 25, 2018, 3:16pm UTC](https://community.pix4d.com/t/help-with-tieing-imported-points-to-photos-for-reoptimization/6940/1 "2018-07-25T15:16:06Z")

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I have performed initial processing on my map, and I have imported my control file with several control points to tie to the map. When I click on a point, it does not find any photos for me to click to associate it to the map because it is far off the map. I just want to click a pixel in the viewport near my aerial target, tell it which control point this is, and click through the photos. The button “connect to tie point” sounds promising, but it is ALWAYS grayed out. Any ideas? I know I can manually type in coordinates after clicking a spot on the map, but this is clearly ridiculous since the point with those coordinates is right there in my list.

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**Author:** ![Daniel\_Rico\_Cordero](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/daniel_rico_cordero/32/187_2.png) [@Daniel\_Rico\_Cordero](https://community.pix4d.com/u/Daniel_Rico_Cordero)\
**Post date:** [July 27, 2018, 12:53pm UTC](https://community.pix4d.com/t/help-with-tieing-imported-points-to-photos-for-reoptimization/6940/2 "2018-07-27T12:53:43Z")

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Hi Blair,

The functionality “connect to tie point” is used to manually calibrate photos which have not been calibrated after step 1.  
You can find more information&nbsp;[here](https://support.pix4d.com/hc/en-us/articles/202560189-How-to-manually-calibrate-uncalibrated-Cameras-in-the-rayCloud). It is the right tool to be used when measuring GCPs.  
More information on how to measure GCPs&nbsp;[here](https://support.pix4d.com/hc/en-us/articles/202560109-How-to-import-and-mark-GCPs-in-the-rayCloud).

Anyway, after processing step 1, the software should be able to estimate where the GCPs are located and in which images they are displayed.  
If this does not happen and they are far off the map, we would recommend investigating why that is happening. Most probably,&nbsp; a wrong coordinate system was selected.

Regards.