"feet" in CAD

A foot by any other name would smell just as bad.....

The only time there is a difference, between International Foot and US Survey Foot, is when you convert to/from meters.

You might try doing a conversion in the software and seeing what answer it gives you.

Dugger

Edit-Get yourself the latest version of Corpscon and do all of your converting there, you can't go wrong then....

[sarcasm]Well, things can still go wrong, you just have to work harder at it>>>Going wrong.....:snarky: [/sarcasm]

I dunno Half, I have all of my CAD drawings set to Parsecs.

🙂
Loyal

Isn't there a song they always play at wedding receptions about feet?

...ya put your left foot in.. ya pull your left foot out... ya put your right foot in and shake it all about....

But seriously, each state has their specific "feet" standard. Don't know WA, but for some reason AZ is Int. I think the only time you'll see any significant differences is when you try and apply them to SPC. Then you'll find the shift you're looking for and/or trying to avoid.

Don't know about your software, but a couple OPUS checks will tell you the answer.

PS - keep your total station scale factor at 1.0000000000000 or you will ruin somebodies day... GPS has it's own issues.

... and then you shake it all about...;-)

That would be the HOKEY POKEY

B-)

type "units".

Big ol' difference when you are scaling state plane coordinates from the origin ... hence my concern. I'm scaling something that should fit and doesn't ... leads me to wonder WHICH foot Carlson means ... when I type "units" it gives me various choices, one of which is "feet" but it doesn't say WHICH feet.

Radar has it. In CAD, a drawing unit is a drawing unit. Try using your calculator to convert meters to feet and see which one Carlson is using. Carlson 2012 has the option for using either foot.

What if that's what it really is all about?

> Big ol' difference when you are scaling state plane coordinates from the origin ... hence my concern. I'm scaling something that should fit and doesn't ... leads me to wonder WHICH foot Carlson means ... when I type "units" it gives me various choices, one of which is "feet" but it doesn't say WHICH feet.

A scale factor has nothing to do with a conversion from meters to/from feet.

If you have a State Plane Coordinate in US Survey Foot and apply a scale factor of 0.99999456544345 and use 0,0,0 as the point of origin, your point will move about 40 feet +/- to it's ground location. The same as it would if you used meters or International foot.....

Check Settings -- Drawing Setup. You should be able to specify to Carlson to use US Feet.

Be aware that AutoCAD customary "Feet" units via the INSUNITSDEFSOURCE and INSUNITSDEFTARGET are (I believe) specified to be International Feet.

--
Ladd Nelson

well, that's what I'm wondering. Carlson support seems to think theirs is hardwired to US survey feet ...

Radar -- not concerned about meters to feet. I have feet (unknown) and feet (usft) that are not matching...

Are you saying that you have 2 points with a published distance between them and you have a GPS's position, of what you believe to be the same 2 points, and they don't match?

If you inverse between 2 points, 5000' a part and you use coordinates that are reported to be in US Survey Foot and do the same thing with coordinates that reported to be in International foot, I think you will have to display a lot of decimal places before you will see a difference.....

I might be wrong though..:-S

not gonna matter in 5000' unless you are monitoring something from that far away.

(matters in scaling those shiny state plane coordinates though.)

I guess CAD is basically unitless until you start printing stuff, so the parsecs you put in are the parsecs you get out, until you use some kinda utility that assumes some kind of units for input...

Anyhow, when I scaled some TenThousandLand stuff to state plane it fell just short enough that it could be the difference between the two kinds of feet in this particular place, so now I gotta figure out where in the data chain that is happening. Hence the original question.

I see, says the blind man.....

You're scaling from ground to grid and seeing a difference in what you have and what you were told.....

There are many factors that play into this, besides just the difference in US Survey Foot and International Foot.

Is ALL the metadata correct? What is the origin of both sets of coords?

ok, indeed they are.

I checked my environment variables on Carlson on ye olde work laptop:

INSUNITS 0
INSUNITSDEFSOURCE 1
INSUNITSDEFTARGET 1

So, searching the web for "INSUNITSDEFSOURCE survey feet", found a good explanation at http://www.theswamp.org/index.php?topic=12351.30

So, seems like a scaling issue where the utility I'm using to scale-rotate-move is assuming survey feet and my CAD is assuming international feet.

Or, might just be that missing tenth again.

The coordinates were new and shiny and the two guys in the white van said they were fresh yesterday morning!