Are You Trendy ?
Chandoo is off Holidaying teaching excel in the Maldives and has lent me the keys to his Blog (Chandoo.org) and this week I plan to take it for a spin.
I will be posting 3 posts on Trend Analysis/Forecasting using Excel and a forth post on some Hidden Worksheet Properties which I stumbled onto last week !
Hopefully if I look after the Blog while Chandoo is gone, He will let me borrow the keys another day.
Forecasting
“Tomorrows weather will be fine and hot with a chance of showers in the morning.”
We have all seen this type of forecasting during the nightly news.
This week I am going to go through the basics of forecasting and trend analysis using Excel as a tool.
We will look at some simple trends and make predictions about future values.
In later posts we will look at more complex data and other methods of tackling these analysis.
Introduction
Often you may have a set of data and need to know what an intermediate or future value of that data may be.
This week we will investigate 3 methods of tackling this problem using Excel.
In this post we’ll look at doing forecasting manually
In the second post we’ll look at a few excel functions that assist us with forecasting
The third post will discuss a method of looking at any value along an Excel generated Trend Line and give you a tool to assist you in this.
Manual Forecasting
In all environments where numbers are collected and people make use of these numbers the ability to forecast or extrapolate data may be required.
In forecasting we are going to look at the trends that the data has and use these trends to help forecast future values or values outside the measured data. The trends can also be used to infill data where gaps may be missing in the collected data.
This post will look at doing this manually, albeit with some help from Excel.
We will examine a business that makes things and we will measure some measurement of those things every 5 days. In trend analysis it doesn’t matter what you measure or what your measuring it against.
We have collected some data which is tabulated
| Day | Measure |
| 5 | 7 |
| 10 | 10 |
| 15 | 24 |
| 25 | 30 |
| 30 | 40 |
One of the easiest ways to visualise this relationship is to draw a quick chart of one measure vs a base or in our case a time line.
This can be shown graphically as a simple Excel Scatter chart
You can see that there is some level of variability in the measurement as the data doesn’t quite fit a straight line.
Manually we can make an estimate of a line of best fit and draw it on the chart by adding a new data series consisting of 2 points.
There are 3 quick methods of using this line of best fit
- Manual Estimates
- Equal Triangles
- Equation for the line
Manual Estimates
If we want to know what the measurement would be for a location where no measurement was taken we can use the chart and 2 quick lines to show in this example that for 20 days we would expect a measurement of about 26 units.
This can also be used for extrapolation of our data past the limits of what was measured.
By extrapolating the Line of Best Fit beyond the data, the same technique can be applied to estimating what some future value maybe.
Equal Triangles
Equal Triangles is a technique where a simple ratios of 2 similarly shaped but different sized right angle triangles can be used to make estimates of missing or extrapolated data.
Using Equal Triangles the ratio of the height to the width of Triangle 1 (Red) is equal to the ratio of the height to the width of Triangle 2 (Blue).
So in the example above
Y1/X1 = Y2/X2
Y1 = 38 – 8 = 30
X1 = 30 – 5 = 25
Y1/X1 = 30/25 = 1.2
So for Triangle 2
Y2/X2 = 1.2
Y2 = ? – 8
X2 = 20 – 5 = 15
from Y2/X2 = 1.2
(? – 8 ) /15 – 1.2
We can rewrite this as
? = 8 + 1.2 x 15 = 26.0
Or
Unknown Y = Min Y + Ratio x (New X – Min x)
Once we have an equation we can setup a new series on out chart based on an equation in some cells and then directly plot the data onto our chart.
In this case we have used the equation =F105+1.2*(E111-E105)
Equation of the line of Best Fit
If we are using a straight line to model our line of best fit, we can also write an equation for the line in the form
Y = mX + c
Where: Y is the unknown measure
X is the X value for which we want to know the value of Y
m is the gradient of the line
c is the Y intercept of the line (or Y value when there is no X value or X =0 )
The gradient m is calculated as the Rise / Run or in our example 30/25 = 1.2
The Y Intercept is the value when x = 0. This can be back calculated from the first point (5,8)
C = 8 – (5 x 1.2) = 2.0
So the equation for our line of best fit is Y = 1.2 X + 2
We have used this in the next example =E136*1.2 + 2
The good thing about having an equation for the line is that we can use that to calculate any value of our measure.
So if we want to know the measure on a day outside the range we measured, say the 40th day
Downloads
You can download examples of all the above charts from the following link
https://chandoo.org/wp/wp-content/uploads/2011/01/Trends1.xls
Benefits of Manual Estimation
- Applicable to simple models
- Can be used without a computer or a calculator in the field
- Gives the user a better feel for the data
Problems of Manual Estimation
- Only applicable to simple models
- Reliant on the accuracy of your estimate of the trend
- No measure of how accurately your estimate fits the data
Next:
In the next post we will look at using excel functions to automatically estimate lines of best fit and other excel functions to aid in estimation of non-linear functions.
Further Readings
38 Responses to “Time to showoff your VBA skills – Help me fix ActiveSheet.Pictures.Insert snafu”
I tried your code with 2003, it works.
But, I know Addpicture does not take URLs anymore with 2007 onwards, perhaps its the same with picture.insert as well.
http://support.microsoft.com/kb/928983/en-us
The above link gives the solution as "picture fill in a shape such as a rectangle".
Tried to recreate this, but it worked fine for me. I just took the image of the error you showed in the post. Is there more info that can narrow this down a bit?
Don't know if this helps?
http://www.theserverside.com/discussions/thread.tss?thread_id=47101
Hi
Not sure if this is what you're after, but I just tried this
Sub Macro1()
ActiveSheet.Pictures.Insert("http://www.google.co.uk/intl/en_uk/images/logo.gif").Select
End Sub
Tied a button to it on the sheet and it seems to work; hope this helps a little
Ian
@All.. the issue is in Excel 2007. In 2003 ActiveSheet.Pictures.Insert seems to work fine. Unfortunately, I have design this in Excel 2007.. that is why I posted it here..
v2
Sub Macro1()
Set n = ActiveSheet.Pictures.Insert("http://www.google.co.uk/intl/en_uk/images/logo.gif")
With Range("c12")
t = .Top
l = .Left
End With
With n
.Top = t
.Left = l
End With
End Sub
Ian
That didn't come out very well. This positions at c12, so can change easily:
Sub Macro1()
Set n = ActiveSheet.Pictures.Insert("http://www.google.co.uk/intl/en_uk/images/logo.gif")
With Range("c12")
t = .Top
l = .Left
End With
With n
.Top = t
.Left = l
End With
End Sub
Works OK in 2007
Ian
The above codes work fines to my EXCEL 2007. Thanks.
Chandoo:
Try 'ActiveSheet.Pictures.Insert'
With ActiveSheet.Pictures.Insert("C:\Example.png")
.Left = ActiveSheet.Range("A1").Left
.Top = ActiveSheet.Range("A1").Top
End With
activesheet.pictures.insert "C:\Documents and Settings\Jon Peltier\Desktop\2007 stuff\insert_charts_2007.png"
Works for me in 2003 SP3 and in 2007 SP2.
Check the URL, and make sure you have internet connectivity.
What also works, and is newer (pictures.insert was supposedly deprecated in '97):
activesheet.shapes.addpicture "C:\Documents and Settings\Jon Peltier\Desktop\2007 stuff\insert_charts_2007.png", false, true, 200,200,100,100
Unfortunately you must specify dimensions (the last four arguments) and you don't necessarily know them. But the picture size is still related back to the original picture size, so you could use scaleheight and scalewidth to fix this.
Chandoo: I just re-read your post.
The code I posted works for me. However, I'm using a local picture. If you try to add a picture from the web, this won't work.
I remember solving this problem before by adding a rectangle shape first, then using the Shapes.AddPicture method to get a picture from the web.
I'll find that code and post it here.
Some more updates... The code "ActiveSheet.Pictures.Insert (path)" works fine in Excel 2007 at home. Strange it failed miserably on my work laptop. Do you think this has got something to do with SP2 of MS Office 2007 or something like that?
@Ian, Jon: Thanks for the code snippets. I guess I will use my home installation of excel to do this.
Chandoo:
Try this on your work laptop:
Sub test()
ActiveSheet.Shapes.AddShape msoShapeRectangle, 50, 50, 100, 200
ActiveSheet.Shapes(1).Fill.UserPicture _
"http://www.datapigtechnologies.com/images/dpwithPig6.png"
End Sub
FYI:
http://support.microsoft.com/kb/928983/en-us
I didn't mean to post code with a local file, because both approaches worked with an internet image as well. This is in Excel 2007 SP2.
activesheet.pictures.insert "http://peltiertech.com/images/2009-07/col_area_noblanks.png"
Jon: Looks like I have SP1 on my client machine! I wasn't paying attention.
Just checked my home computer where I have SP2, and you're right...looks like they fixed it.
I didn't even bother testing in SP1, though I could if anyone cares enough.
I'm afraid I don't have a solution, but I find it remarkable that after attaining a certain status in the Excel world, Chandoo does not need to post on an Excel discussion forum to get help for an Excel problem. Instead, he posts on his blog and all the gurus come rushing to his help.
Isn't Web 2.0 great?
Teylyn - I saw Chandoo's tweet first, and followed the link back to his blog.
@Mike.. thank you. I have seen the fill rectangle solution before posting the query here. For that matter, I have also tried the solution of embedding a browser control on a spreadsheet. both of these seemed a bit extreme. That is why I have asked it here.
But I guess I will end up using it if I had to build this in work laptop.
@Teylyn: I have thought of posting this in a forum. (Unfortunately I have not been to any excel group in the last 5 years. Last time I was active was when I built a jave based excel sheet construction solution using POI.HSSF classes of Apache... ) After searching for a few hours, I found several forum posts where others had same problem and the solution recommended (using .left and .top parameters) is not working for me. Incidentally most of these solutions are from a certain Jon Peltier 😛
I thought may be the problem is interesting for fellow blog readers. So I posted it here.
Hi,
Adapting the code in the question,
[code]
Sub InsPicture()
pPath = "http://chandoo.org/images/pointy-haired-dilbert-excel-charts-tips.png"
With ActiveSheet.Pictures.Insert(pPath)
.Left = Range("a1").Left
.Top = Range("a1").Top
End With
End Sub
[/code]
Seems to work fine
Looks like it was a problem in 2007 up to SP1, which was corrected in SP2.
@Jon.. seems like the case. I just checked the version at work laptop. it is 12.0.6331.5000 (SP1).
Thank you so much every one. I really appreciate your time and suggestions in solving this.
Glad to help. I couldn't understand why something so straightforward wasn't working.
Hi All
Is there a way of inserting a motion clip eg animated gif or swf or flv?
Thks
You can insert animated GIFs by inserting them in a browser control through VBA. For other types of movies, I can guess you can insert them as clip art.
I WANT THE INSERT PICTURE BY USING COADING
so currently i was struggling same as you, chandoo, with the insert picture method in excel 2007/10 from an url and came along your thread here.
so i re-designed the code on the addshape method as mike was suggesting it and all of the sudden it works just fine.
thanks alot to you guys, you were a great help
a big salut from switzerland
Hi guys,
I need help copying and pasting an image with the path in a cell.
I leave the code.
And thank you very much!
Sub Copiarimg()
Dim pic As Picture
With ActiveSheet
Set pic = .Pictures.Insert(Range("f2").Value)
With .Range("e9:g22")
pic.Top = .Top
pic.Left = .Left
pic.Width = .Width
pic.Height = .Height
End With
End Sub
I've played around with the approaches in these comments, and the code below is what I've come up with. The ImagePath can be a local file or a URL. As Jon mentioned above, the trick is to set an arbitrary value for the width and height, then call the ScaleWidth and ScaleHeight methods afterward to reset the picture to its original size. Once the LockAspectRatio property is set, you can change the picture width and the height will automatically scale (or vice-versa).
Sub AddPictureToRange(TopLeftCellAddress As String, ImagePath As String)
Dim pic As Shape
Dim l As Single, t As Single
Dim temp As Single
l = Me.Range(TopLeftCellAddress).Left
t = Me.Range(TopLeftCellAddress).Top
temp = 10# ' arbitrary value
Set pic = Me.Shapes.AddPicture(ImagePath, msoFalse, msoTrue, l, t, temp, temp)
pic.ScaleHeight 1#, msoTrue
pic.ScaleWidth 1#, msoTrue
pic.LockAspectRatio = msoTrue
End Sub
I need some help with inserting pictures. I have an excel file with a column of item numbers next to this row I want to insert a picture of this item. The pictures are coded with the item number so I tried to insert it with one of the codes above:
Sub InsPicture()
pPath = "http://img.bricklink.com/P/80/55236.gif"
With ActiveSheet.Pictures.Insert(pPath)
End With
End Sub
That worked but I need to do that for every row separtly.
So I tried in the code
pPath = "http://img.bricklink.com/P/80/"&Text(a1;"#")&".gif"
But that gives errors.
Anybody ideas?
Hi Nicholas, I used your solution in a related problem in Excel 2003 and it worked flawlessly..thank you!
Hi Mike Alexander,
Your solution with some changes was helpful in my problem in XL 2007, thanks.
Hi,
thanks all. In addition, I had a problem with multiple pictures inserting (every new picture replaced the prior one). I've changed it a bit, may be helpful..
Sub test()
ActiveSheet.Shapes.AddShape msoShapeRectangle, 50 , 50, 100, 200
ActiveSheet.Shapes(1).Fill.UserPicture _
"http://www.datapigtechnologies.com/images/dpwithPig6.png"
ActiveSheet.Shapes(1).Copy
ActiveSheet.Paste
End Sub
Try this instead:
Sub test()
ActiveSheet.Shapes.AddShape msoShapeRectangle, 50 , 50, 100, 200
ActiveSheet.Shapes(ActiveSheet.Shapes.Count).Fill.UserPicture _
"http://www.datapigtechnologies.com/images/dpwithPig6.png"
End Sub
Thanks to everyone, this thread has been very helpful. However, image inserting still doesn't work quite as expect for me.
While I can get a picture inserted into an Excel 2010 worksheet using either:
1) ActiveSheet.Shapes(ActiveSheet.Shapes.Count).Fill.UserPicture...
2) ActiveSheet.Pictures.Insert(pPath), and
3) Shapes.AddPicture...
unfortunately the images all insert with a display size determined not by the actual pixel dimensions of the image but by the dpi resolution.
So for example, if I insert two copies of the exact same 600x600 pixel image, one with a 300dpi resolution and the other with 72dpi, they display at vastly different sizes on screen.
While this might be intended behaviour for Excel in order to maintain a WSYWIG printing layout, I actually need a way to insert the image based on the the actual pixel dimesnsions and ignoring the dpi resolution.
Any help appreciated.
Thanks
Kez
Not doing an intentional bump, but realised I posted in rely to one of the repsonses here instead of to the main thread, so reposting.
=====
Thanks to everyone, this thread has been very helpful. However, image inserting still doesn’t work quite as expected for me.
While I can get a picture inserted into an Excel 2010 worksheet using any of the below methods:
1) ActiveSheet.Shapes(ActiveSheet.Shapes.Count).Fill.UserPicture....
2) ActiveSheet.Pictures.Insert(pPath), and
3) Shapes.AddPicture....
unfortunately the images all insert with a display size determined not by the actual pixel dimensions of the image but by the dpi resolution.
So for example, if I insert two copies of the exact same 600×600 pixel image, one with a 300dpi resolution and the other with 72dpi, they display at vastly different sizes in Excel on screen.
While this might be intended behaviour for Excel in order to maintain a WYSIWYG printing layout, I actually need a way to insert the images based on the the actual pixel dimesnsions and ignoring the dpi resolution.
Any help appreciated.
Thanks
Kez
Well, answered my own question 🙂
For those who might be interested, you can use this function:
Public Function GetPicDims(strFilePath As String, strFileName As String) As String
GetPicDims = CreateObject("Shell.Application").Namespace((strFilePath)). _
ParseName(strFileName).ExtendedProperty("Dimensions")
End Function
to get the dimensions of the image you want to insert. Then you can parse the return string and use the width and height values to add a rectangle shape of the appropraite size, like:
ActiveSheet.Shapes.AddShape msoShapeRectangle 50, 50, iWidth, iHeight
which you then fill with the picture:
ActiveSheet.Shapes(ActiveSheet.Shapes.Count).Fill.UserPicture "c:\temp\test.jpg"
This way the picture gets inserted using the pixel dimensions and the (print) resolution gets ignored.
If desired, the GetPicDims function can be made more generic to get other ExtendedProperties.
Regards
Kez