# Reference Point COGO

**URL:** <https://forums.buildingsmart.org/t/reference-point-cogo/3281>\
**Category:** Developers\
**Created:** [January 15, 2021, 3:04pm UTC](https://forums.buildingsmart.org/t/reference-point-cogo/3281 "2021-01-15T15:04:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kevin.nahaboo](https://avatars.discourse-cdn.com/v4/letter/k/7bcc69/32.png) [@kevin.nahaboo](https://forums.buildingsmart.org/u/kevin.nahaboo)\
**Post date:** [January 15, 2021, 3:04pm UTC](https://forums.buildingsmart.org/t/reference-point-cogo/3281/1 "2021-01-15T15:04:37Z")

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Hello everyone,

We are looking for IFC equivalent of “Reference Point” or “COGO”.  
• Position for PIs;  
• Limits of a parcel;  
• Position of Light Pole;  
• Vertical Signal;  
• Representative Trees;  
• Manhole position; or…  
• Simply reference coordinate;  
• Etc.  
•

With IFC we have IFCGeographicalElement but we are not sure it would fit for all cases.  
Moreover there is no specific entities to describe coordinates (Lat/Long and UTM).

Is there any work in progress on that topic?

Thank you in advance.

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**Author:** ![stefan.markic](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/stefan.markic/32/168_2.png) [@stefan.markic](https://forums.buildingsmart.org/u/stefan.markic)\
**Post date:** [January 18, 2021, 3:23pm UTC](https://forums.buildingsmart.org/t/reference-point-cogo/3281/2 "2021-01-18T15:23:48Z")

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For a reference coordinate (e.g. in UTM), you should have look at entities `IfcMapConversion` and `IfcProjectedCRS` (versions IFC4 and up). The rest can be placed relatively to that reference point (like trees, border points, etc.) using `IfcObjectPlacement` and its derivatives. See Figure 7 [here](https://publications.cms.bgu.tum.de/2018_Markic_ICCCBE.pdf) for a schematic.

There is a good paper on different possibilities on georeferencing IFC model data [here](https://jgcc.geoprevi.ro/docs/2019/10/jgcc_2019_no10_3.pdf). I agree with authors’ assertion that only LoGeoRef 50 is the only option with enough data for precise localization.