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Decimal minutes

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(@stacy-carroll)
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Every once in a while I follow a surveyor that sometimes used degrees, minutes, decimal minutes instead of the usual degrees, minutes, seconds. His plats are the only ones I ever recall using that format. The inexperienced crew chief could get burned by mistakenly trying to use the decimal minutes as seconds. The first time I encountered that format, I wasn't sure about my interpretation until I tried closing the plat. Probably took half an hour since I had to convert every course to ddmmss. I couldn't figure out how to get the hp48 data collector to accept the ddmm.m format. Was that format common in other areas?

 
Posted : 19/03/2023 12:23 am
(@mathteacher)
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The scary part is that decimal minutes is common in recreational GPS.

 
Posted : 19/03/2023 3:46 am
GaryG
(@gary_g)
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NeveR saw that. I have seen decimal seconds, and just wonder WHY?

 
Posted : 19/03/2023 4:14 am
(@antcrook)
Posts: 278
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NMEA output is in degrees, minutes, decimal minutes. 

 
Posted : 19/03/2023 8:57 am
(@glenn-borkenhagen)
Posts: 410
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Perhaps the surveyor whose work the OP was following was using an instrument like the Wild T16, which reads to minutes and then you interpolate to get the seconds.  It is pretty easy to estimate to tenths of a minute and multiply by 60 for the seconds. 

Perhaps the surveyor in question skipped the multiply-by-60 part and just reported the decimal minutes?

GB

 
Posted : 19/03/2023 3:28 pm
(@stacy-carroll)
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That surveyor was a dual registrant and practiced until the late 90's (or thereabouts). He was the only one at that time that regularly ran Astronomic North. His surveying was well above average. 

 
Posted : 19/03/2023 5:19 pm
(@jim-frame)
Posts: 7277
 

Every once in a while I follow a surveyor that sometimes used degrees, minutes, decimal minutes instead of the usual degrees, minutes, seconds.

I've seen it on a few old maps around here.  It's not common, though.

 
Posted : 19/03/2023 8:17 pm
(@david3038)
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That surveyor was a dual registrant and practiced until the late 90's (or thereabouts). He was the only one at that time that regularly ran Astronomic North. His surveying was well above average. 

I'm guessing Mr. Downs?  I love following his surveys.

He liked to have some odd graphic scales too.

He got his start with Mr. McLeroy.

 

 
Posted : 20/03/2023 3:20 am
(@stacy-carroll)
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@david3038 

Yes, you are correct. I didn't know where he got his start! I enjoy following his work as well. Is Mr. Downs still living?

 
Posted : 20/03/2023 6:31 am
(@david3038)
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@stacy-carroll 

He is but is not well. 

 
Posted : 20/03/2023 7:53 am
(@chris-bouffard)
Posts: 1440
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I've never seen it in my 40 years surveying.

 
Posted : 24/03/2023 11:46 am
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