Getting value on Y axis by putting X axis value

[kashifjillani]

Hello to all the experts of Excel,

I still can not figure out the way to get the values in a chart/graph by putting an specific X axis value.

e.g.

There is relation between Gauge height and Flow

<TABLE style="WIDTH: 96pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=128><COLGROUP><COL style="WIDTH: 48pt" span=2 width=64><TBODY><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; WIDTH: 48pt; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 width=64>Gauge</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; WIDTH: 48pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" width=64>Flow </TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.305</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>0</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.32</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>0.10022</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.341388</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>0.27539</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.381347</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>0.85528</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.401708</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>1.32224</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.413752</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>1.69248</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.433354</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>2.46828</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.452996</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>3.43106</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.482379</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>5.3022</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.511557</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>7.77429</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.522962</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>8.9451</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.561209</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>13.53592</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" height=20 align=right>0.589</TD><TD style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; BACKGROUND-COLOR: transparent; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0" align=right>17.68</TD></TR></TBODY></TABLE>


If I draw the curve with Flow on X-axis and Gage on Y-axis and then want to know the flow at Gage 0.53m.

OR

By putting flow value to know Gage height.

Regards,

 

[DrSingh]

Thanks a ton Jon, you have solved my problem. Thanks.

 

[Josm95]

Hi Jon,

I knowit's an old post but this seems to be a solution for my problem.
However I have a problem. This is my data:

x	y
39	1000
42	500
48	200
56	100
70	50
110	20
125	10
125	5
125	2
125	1
125	0,5
125	0,2
125	0,1
151	0,05
500	0,02
12500	0,01

<tbody>
</tbody>

When i try to find y for x=2000 for example, the y that is calculated is not exact. It is giving an y value that is higher.
Now i added a trendline of the line 500-12500/0,02/0,01 (where my x=2000 is in between), and I can see that the y that was estimated according to the trendline somehow.
The trendline is set to ''Lineair'', so i guess thats how your formule calculates the y, when i set the trendline to ''power'', it gives a correct trendline, but of course it doent change the calculated y value.
Now the question is, how can i change it to get it working?


Red=data
Green=calculated y for x=2000
Purple=test line with trendline

I already tried changing the matchtype to -1 (for decreasing values),that didnt work.

Hope someone can help me,

Regards,

Jos

 

[Josm95]

Something wrong with the picture, here it is:

https://imgur.com/LZ03Yy1

 

[Jon Peltier]

The interpolation routine here is a linear interpolation not because of any trendline setting, but because those are the formulas presented. A linear interpolation finds a point on a straight line connecting two points on a chart with linear axes.

To interpolate a power law, you need to take logarithms of the X and Y values and repeat the linear interpolation. This will find a point on a straight line connecting two points on logarithmic X and Y axes.

No need to change the MATCH type to -1, because you are searching through increasing X values (column 1) to find the match. Here are the formulas:

A2: X value for which you want to find Y (or log X for which you want to find log Y)
A3: =MATCH(A2,A6:A21,1)
B2: =(A2-INDEX(A6:A21,A3))/(INDEX(A6:A21,A3+1)-INDEX(A6:A21,A3))*(INDEX(B6:B21,A3+1)-INDEX(B6:B21,A3))+INDEX(B6:B21,A3)

 

[Josm95]

The interpolation routine here is a linear interpolation not because of any trendline setting, but because those are the formulas presented. A linear interpolation finds a point on a straight line connecting two points on a chart with linear axes.

To interpolate a power law, you need to take logarithms of the X and Y values and repeat the linear interpolation. This will find a point on a straight line connecting two points on logarithmic X and Y axes.

No need to change the MATCH type to -1, because you are searching through increasing X values (column 1) to find the match. Here are the formulas:

A2: X value for which you want to find Y (or log X for which you want to find log Y)
A3: =MATCH(A2,A6:A21,1)
B2: =(A2-INDEX(A6:A21,A3))/(INDEX(A6:A21,A3+1)-INDEX(A6:A21,A3))*(INDEX(B6:B21,A3+1)-INDEX(B6:B21,A3))+INDEX(B6:B21,A3)

Thanks Jon,

I fixed it on a similar way, not by adding a table with the log values but by changing the lineair interpolation formula to the logarithmic one, which is basically the same. But i needed the original values on the x and y axis. It all works.

Thanks for the respond!