How to find out scale of plan and profile from a print out.

[Ish]

Dear team,

Any one have formula or tips , tricks to find the horizontal scale and vertical scale from a print out of road plan and profile.

Paper size : A2

drawing : Road plan and profile.

What is the scale horizontal and vertical ?

 

thanks

[rkmcswain]

Well obviously, there must not be a scale printed on the sheet?

 

Is there anything marked with a dimension? Like 100' ROW, or stationing along a road ?

[RobDraw]

Rule of thumb is to not scale from printed drawings.

 

If you choose to ignore this rule, look for something with a known size. Measure and extrapolate.

[BIGAL]

Metric makes it easy 1000/scale = multiply factor, so 1:50,  dist/20 = true distance, but as mentioned, if FIT used to print even more likely to be wrong.

[eldon]

17 hours ago, Ish said:

......Any one have formula or tips , tricks to find the horizontal scale and vertical scale from a print out of road plan and profile.

Paper size : A2

drawing : Road plan and profile.

What is the scale horizontal and vertical ?......

 

Look at what is written on the print out.

 

Is there a title block? If not, then you have not got the complete print out.

 

Have you got a scale ruler? In the last resort, you could try guessing the scale by measuring features.

 

Post a copy of the information that you have, and let us guess with you.

[Ish]

On print out written scale remove by interviewer.

There was a title block on A2 .

Interviewer give me a steel ruler only to find out horizontal and vertical scale.

 

Finally I just guess.only

 

Now looking correct method to find solution.

 

Thanks

[RobDraw]

It's a trick question!

 

Give him the scale back and say, "I don't scale off of drawings."

[eldon]

On the profile, there should have been chainages and elevations. Perhaps this is a test on how well you can read a drawing.

 

It would be a matter of arithmetic to find out distances in both the horizontal and vertical directions. Then using the steel rule to measure the paper distances, you can then work out the horizontal and vertical scales. Normally they would be conventional scales, but the interviewer could be being tricky!

 

Good luck in searching for any other method.

[BIGAL]

Like Eldon "arithmetic"  re read my post.

[ammobake]

Do you have the PDF?

 

The stations will typically be incremental (civil context) with the scaling of the plan view being more exact, typically.

 

The profile views can sometimes be dimensionally accurate horizontally but exaggerated vertically by the software for depiction purposes.  But the horizontal dimension of the profile view of the road, path, or feature is going to give u a more accurate idea of exact scale, I think.

 

So if it is a road, for example, EOP to EOP would be your reference dimension. (edge of pavement)

 

The width of the road, path or feature would typically be called out somewhere on the plan view or elsewhere in the set.

It is possible to figure out exact scaling using that dimension as a reference.

 

If the sheet depicts a new paved road that is 40 feet wide, you can use that info to your advantage.

At that point u know EOP to EOP is exactly 40 feet. 

 

if your EOP to EOP on the sheet is exactly 4 inches, you already know your answer. So it's just doing the math, as already mentioned.

 

There are other tricks if the scale is non-standard.

For those, I would scan in the profile view to a PDF and use the software to do most of the heavy lifting.

 

-ChriS

 

[BIGAL]

A side comment did lots of checking using a 1200mm ruler to compare inaccuracy of plotting a A1 36x24 for feet people and compare to known measurements and  found tolerance was not that match over the full length. At 1:1 was like 1/2mm, fit 1.5mm depending on how created.

[RobDraw]

Add some more for reproduction errors, reduced size print an multiply that by the scale factor.

[Jonathan Globerson]

Scaling a drawing not a good drafting practice. Drawings should always be made to 1:1 scale in model space. Viewports are used in paper space for showing the information in magnified view.

The requirement of scaling a drawing without changing dimensions arises in those drawings where model space is used for plotting.

System variable “DIMLFAC” controls what fraction of measurement is to be shown in dimensions. When DIMLFAC is 1, a line measuring 25 units will be displayed as 25 in the dimension. If this value is set to 2, it displays as 50.

After scaling this line by 2, its measurement becomes 50. Setting DIMLFAC to 0.5 will force to display the dimension as 0.5x50=25. Thus, scaling will not alter the dimension value.

However, this is not a recommended practice and AutoCAD help documents encourage retaining DIMLFAC value as 1.

 

Your Regards

Jonathan Globerson 

CEO at GloberDesign