I have used Rhino 7 on Mac for a bridge and subsequent park project on my property. I have modeled the enclosed park which now contains numerous native plants. I have added 3D Modelled shrubs and trees and know the coordinates. I want to now use iRhino 3d on my iPad and in the field note the locations of newly planted items and then be able to go back and analyze those points and update a large Excel sheet with the coordinates and species type. Just getting started and welcome any advise.
If I understand you correctly, you are looking for an AR (augmented reality) feature that gives you the coordinates of a point as you walk around your property.
We don’t currently have such a feature in iRhino3D. I’m working on adding support for geotracking using Apple’s ARKit but I suspect even that won’t help your case because:
Generally GPS on smartphones and tablets provide an accuracy of about 5 meters. To place location anchors with precision, geotracking requires a better understanding of the user’s geographic location than is possible with GPS alone. Based on the user’s GPS coordinates, ARKit downloads imagery that depicts the physical environment in that area. Apple collects this localization imagery in advance by capturing photos of the view from the street and recording the geographic position at each photo. By comparing the device’s current camera image with this imagery, the session matches the user’s precise geographic location with the scene’s local coordinates.
This means that high accuracy coordinates will only be available in areas that an Apple Maps car has visited before. So unless an Apple Maps car has somehow entered your property, that won’t work 
You can read more about Apple’s geotracking technology here: ARGeoTrackingConfiguration | Apple Developer Documentation
Thanks for getting back so quickly. I am aware of the limitations of gps. In my case I already have the part, fence posts and already existing trees and plants located with their coordinates. What I want to do is walk with the iPad and where I see a plant near a known landmark, place ax “x” and maybe a text note. Later I hope to open that field file on my main desktop Mac and retrieve those field coordinates and place the appropriate model into the Master.
I see, in iRhino3D you can create markups.
This allows you to draw on top of existing view and annotate things. These markups will get saved on your device and are accessible in iRhino.
However they’re not supported in Rhino for desktop at this point. If you need to review them in desktop you can just export them as images from the markup menu.
Does this help?