# Scale 1:25 or 1:75 why scale ruler first reading is 0.5m and....

Dear folks

Yes I do understand scale ration 1:25 means 1 unit on a map equal to 25 units on a real and scale ration 1:75 means 1 unit on a map equal to 75 units on real

Question my Kent tri scale ruler for the ratio 1:25 showing first number as 0.5 m (i.e 50 cm, 500 mm)

While first reading for ratio 1:75 as 1 m (100 cm, 1000mm).

My confusion for the ratio 1:25 ruler has 25 small tiny line between 0 and the next reading,,, means there are 25 units right ? if we times 25 tiny lines x 25 mm = 625 mm not 500 mm
http://imgur.com/a/CmVFe

Same thing for the ratio 1:75 ruler has 20 small tiny lines between 0 and the next reading means there are 20 units right ?? 20 yimy lines x 75 = 1500 mm not 1 m
http://imgur.com/a/42AyT

Thanks

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My confusion for the ratio 1:25 ruler has 25 small tiny line between 0 and the next reading,,, means there are 25 units right ? if we times 25 tiny lines x 25 mm = 625 mm not 500 mm
http://imgur.com/a/CmVFe
No, you are reading it wrong. You need to follow the graduation. Since there are 25 marks in what corresponds to 0.5 m, each mark corresponds to 0.5 m/25 = 0.02 m = 2 cm. You also clearly see that the 0.5 m on the 1:25 scale takes up 2 cm as it should (2 cm x 25 = 50 cm). Why do you think each mark should correspond to 25 mm?

No, you are reading it wrong. You need to follow the graduation. Since there are 25 marks in what corresponds to 0.5 m, each mark corresponds to 0.5 m/25 = 0.02 m = 2 cm.
When you divide 0.5 m by 25 tiny lines (divisions) yes I do agree that each division is 2 cm ( 20 mm)

Why do you think each mark should correspond to 25 mm?
Don't you think below quote agree with what I understood for each tiny lines ?
http://www.archaeologica.org/Drawing%20to%20Scale.htm
http://www.archaeologica.org/Drawing%20to%20Scale.htm
Here they consider tiny division (i.e mm) and each tiny line on ruler is 200 mm on real
Let's start with the scale at the top labeled 1:200. Imagine that you lay this scale on your piece of paper and draw a line from the 0 to the number 5. You just drew a line that is 5 meters long at 1:200,meaning that if you measured this line on the paper, every millimeter would be equal to 200 millimeters on the original object you are drawing.

https://www.dlsweb.rmit.edu.au/toolb...l/04scales.htm
Here same as above they consider tiny division and they multiply them by the used scale to find real dimension on real
The photo below shows measuring diagonally with a ruler from a wall corner to a wall corner on a site plan.The measurement on the ruler is 78 millimetres ( 0.078 metres). The scale is 1:200. Therefore the actual size would be 15.6 metres (0.078m X 200).

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When you divide 0.5 m by 25 tiny lines (divisions) yes I do agree that each division is 2 cm ( 20 mm)

Don't you think below quote agree with what I understood for each tiny lines ?
http://www.archaeologica.org/Drawing%20to%20Scale.htm
Here they consider tiny division (i.e mm) and each tiny line on ruler is 200 mm on real

https://www.dlsweb.rmit.edu.au/toolb...l/04scales.htm
Here same as above they consider tiny division and they multiply them by the used scale to find real dimension on real
No. Neither of those quotes agree with your interpretation. The first discusses real millimeters (not gradings on your scaled ruler) and the second uses a 1:1 ruler.

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Do not make these ratios into something complicated.
1:25 would mean one unit on the paper represents 25 of some other but specified units in real place. Do you have graduations shown on your paper map or scaled drawing?

Your first picture imgur link shows something different than a "drawing". The upper scale suggests 1 unit of some kind, and the corresponding lower scale shows a spanning of "26 to 30" of some other unit. This picture appears to show ratio of 1:4, for the upper_scale to the lower_scale.

Yes this was my confusion ,they are measurement unit not real millimeter