FARO Scene State Plane Coordinate System

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JENGELBRECHT
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Full Name: Joshua Engelbrecht
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Location: San Jose, CA

FARO Scene State Plane Coordinate System

Post by JENGELBRECHT »

Recently we ran into an issue dealing with a project in which our control was shot in on the State Plane Coordinate System. As we exported our point cloud from Scene, put into recap to get an .rcp file, and dropped into our CAD site drawing we noticed a misplacement of approximately 12' in the x and 3' in the y. Checking and double-checking our registration and control registration, we encountered no issues. Even our control points from our .csv file used dropped into CAD perfectly aligning with the columns on which they were placed. So where did this error occur?

Error: When importing our control file originally we used import units of US Survey ft. In order to export a point cloud to put into Recap (to be a compatible and usable point cloud) everyone knows that the file must be in metric in order to go into Recap, so export units set to (m). When converting from US Survey ft to metric, the conversion factor is not taken into account. Meters and international ft have a direct relation, however there is a conversion factor when going from US Survey ft to international ft (which will then be turned into meters). The conversion factor being 1 ft international = 0.999998000004 US Survey ft effects large coordinate values such as those found in state plane coordinates, which when using smaller values like in site specific control with otherwise be negligible. When applying this conversion factor to our (x,y) values in our control which were approximately (6100000,1900000), we came up with a difference in US Survey ft and international ft of 12' in the x and 3.9 ft in the y accounting for our original skew. How do we fix this?

Solution: When applying survey control involving large quantities such as those found when using SPCS, set import units to (ft) before importing your control file, leaving the export units as (m) so you can export to Recap. As far as this has been noted in my experience, this also applies when using any RITHM Application data (follow up with Philip Lorenzo for clarification). If you do not have to convert through Recap leave import and export units as US Survey ft and will be no need for a conversion factor as not changing units.

See video below for troubleshooting workflow!
https://youtu.be/CztE0YmOVyw
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