On Thursday 31 July 2008 12:06:51 James Frysinger wrote:
> I could use the advice here of someone conversant in drawing survey
> plats in metric units. I am reviewing a proposed set of Subdivision
> Regulations for my county and they fail to include metric equivalents,
> which I will push for.
>
> The proposed regulations call for plats to be drawn on 18 in by 24 in or
> 24 in by 36 in paper. What paper sizes are normally used in the metric
> world that are roughly equivalent to that? I'm guessing at A2 and A1,
> respectively. Are those commonly used in drafting of survey plats?

Here in North Carolina the law requires that plats be one of those two sizes 
or 21×30 (762×533.4). ISO sizes are not allowed. I haven't gotten around to 
asking the NCBELS to change that. Not having seen plats on ISO paper, I say 
go with A2 and A1, with B2 if you need one between.

I suggest adding a clause specifying a year after which inch sized paper shall 
no longer be allowed. My original idea was that if 10% of plats are on ISO 
paper in some year, all plats shall be on ISO paper ten years later.

> The statement on scales is that no less than 1 in = 50 ft [which would
> be 1:600] be used with 1 in = 100 ft [which would be 1:1200] being the
> absolute minimum. What typical metric scales should I suggest that are
> roughly equivalent and do not exceed these stated values? I'm guessing
> at 1 mm = 0.5 m [1:500] and 1 mm = 1 m [1:1000], respectively.

The absolute minimum scale should be independent of the measuring unit used, 
so set it to 1:1200. If you set it to 1:1000, then it will be illegal to draw 
at 1 in = 100 ft. The recommended minimum may be different for foot drawings 
than for meter drawings. Both 1:500 and 1:1000 are typical, as is 1:200. I 
drew my map of the Facilities Center at 1:500.

My scale (which is at the office) has 1:500, 1:1000, 1:1250, 1:1500, 1:2000, 
and 1:3000. This is lopsided; there's probably another one that has 1:600, 
1:400, 1:750, and 1:800, or something like that.

The scale should be specified as a ratio. If someone who draws in feet wants 
to say how many feet are drawn as an inch, let him figure it out.

Pierre

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