Recently I saw an interesting Earth Venus cosmic dance video on Facebook. See the original video below or here.
Although this is not entirely accurate from physics & astronomy perspectives, the dance is a stunning example of patterns that are generated by simple things.
I wanted to recreate this cosmic dance in Excel. How else am I to get my spreadsheet fix on a Saturday?
Here is a quick demo of the final outcome. Read on to learn more about the Earth Venus cosmic dance.
The details & assumptions
To create this cosmic dance, we need a few details
- Distance from Sun to Venus & Earth – 67.2 and 93 million KM respectively
- Number of days it takes to rotate around the sun – 224.7 and 365.25 respectively
We will also assume these incorrect things to keep our model simple
- Orbits of Earth & Venus are circular with Sun at center: In reality, they are elliptical, but as these are just stretched circles, we can assume circular orbits to keep the math simple.
- Sun is static: In reality, Sun (and entire solar system) is also moving. This means, this cosmic dance may never occur.
We also need one critical detail to graph this cosmic dance:
- The angular interval for plotting the lines. In the above examples, I have used 10° (ie there will be 36 lines around the circle). This is denoted by named range m in the model. You can adjust this in the output worksheet using a form control. Different values of m yield different patterns (although most of them will be pentagonal).
The math:
Generating planetary co-ordinates:
In a table, we will generate the positions (X & Y co-ordinates) of both Venus & Earth for 3000 points in time, each incremented by m degrees, starting at 0°.
To generate the X & Y values, we will use the x=r.cos? and y=r.sin? equations (where r is the distance from Sun and ? is the angle).
Drawing the lines:
This is the tricky part. At each step in the animation our line should from one tooth of the saw tooth pattern. See this demo to understand.
For more about this technique read – interactive network chart to map relationships between people.
So during each step of the animation, we add more co-ordinates to the chart (scatter plot) to generate this saw tooth pattern. Over time, this will yield the beautiful pentagonal cosmic dance.
We can generate these successive Venus & Earth co-ordinates from the calculations performed earlier by using MOD & INDEX formulas.
Once such saw tooth line data is generated, we will designate a cell to hold current animation position. Let’s call this pos.
We will then create two named formulas – dance.x and dance.y. These will contain the data necessary for our scatter plot. We will use OFFSET formula to generate these dynamic named formulas.
The chart
Now that all the necessary calculations are done, create a scatter plot with the dance co-ordinates. Set up X & Y axis minimum and maximum values accordingly (-160 to 160 should do). This ensures that the chart remains same no matter what step of animation we are on.
Also, add 3 more series to the chart
- One for a dot to represent Venus at current position
- One for a dot to represent Earth at current position
- One for a line connecting Venus to Earth
The animation
Next, let’s add a small macro to animate the chart. This macro will increment pos from 1 to a large number. After each iteration, we will call DoEvents so Excel can re-draw the chart. That is all.
Download the Earth Venus dance workbook
Click here to download the Earth Venus cosmic dance workbook. Enable macros to enjoy the dance. Play with form control to adjust the animation speed and pattern. Examine the data tab to learn more about the calculations.
Did you enjoy the dance?
I really liked the original video on FB and that is why I recreated this in Excel. This is a great exercise to show the power of simple things generating extraordinary patterns.
What about you? Do you like this Earth Venus dance?
More Excel animation and fun:
If you like animating things, you are going to love these tutorials. Check out,
21 Responses to “How to Filter Odd or Even Rows only? [Quick Tips]”
Infact, instead of using =ISEVEN(B3), how about to use =ISEVEN(ROW())
So it takes away any chance of wrong referencing.
I like Daily Dose of Excel
I like it.
Just a heads up, you do need to have the Analysis ToolPak add-in activated to use the ISEVEN / ISODD functions. An alternative to ISEVEN would be:
=MOD(ROW(),2)=0
rather than use a formula, couldn't you enter "true" in first cell and "false" in the second and drag it down and than filter on true or false.
Just for clarification, is Ashish looking to filter by even or odd Characters or rows?
so many functions to learn!
Nice support by chandoo and team as a helpdesk. Give us more to learn and make us awesome. Always be helpful.......
In case you want to delete instead of filter,
IF your data is in Sheet1 column A
Put this in Sheet2 column A and drag down
=OFFSET(Sheet1!A$1,(ROWS($1:1)-1)*2,,)
(This is to delete even rows)
To delete odd rows :
=OFFSET(Sheet1!A$2,(ROWS($1:1)-1)*2,,)
If your numbered cells did not correspond to rows, the answer would be even simpler:
=MOD([cell address],2), then filter by 0 to see evens or 1 to see odds.
I sometimes do this using an even simpler method. I add a new column called "Sign" and put the value of 1 in the first row, say cell C2 if C1 contains the header. Then in C3 I put the formula =-1 * C2, which I copy and paste into the rest of the rows (so C4 has =-1 * C3 and so forth). Now I can just apply a filter and pick either +1 or -1 to see half the rows.
Another way, which works if I want three possibilities: in C2 I put the value 1, in C3 I put the value 2, in C4 I put the value 3, then in C5 I put the formula =C2 then I copy C5 and paste into all the remaining rows (so C6 gets =C3, C7 gets =C4, etc.). Now I can apply a filter and pick the value 1, 2, or 3 to see a third of the rows.
Extending this approach to more than 3 cases is left as an exercise for the reader.
Another way =MOD(ROW();2). In this case, must to choose betwen 1 and 0.
[...] How to Filter Even or Odd rows only [...]
very different style Odd or Even Rows very easy way to visit this site
http://www.handycss.com/tips/odd-or-even-rows/
Thanks for the tip, it worked like magic, saved having to delete row by row in my database.
Thanks!
Thankssssssssssssssss
Hi Chandoo- First of all thanks for the trick. It helped me a lot. Here I have one more challenge. Having filtered the data based on odd. I want to paste data in another sheet adjacent to it. How can I do that?
For Example-
A 1 odd
B 3 odd
C 4 even
D 6 even
I have fileted the above data for odd and want to copy the "This is odd number" text in adjacent/next sheet here. How can I do that. After doing this my data should look like this
A 1 odd This is odd number
B 3 odd This is odd number
C 4 even
D 6 even
Hi! Could you please help me find a formula to filter by language?
Thank you!
Chandoo SIR,
I HAVE A DATA IN EXCEL ROWS LIKE BELOW IS THERE ANY FORMULA OR A WAY WHERE I CAN INSTRUCT I CAN MAKE CHANGES , MEANS I WANT TO WRITE ONLY , THE FIG IS FRESH, BUT IN BELOW ROW IT WILL AUTOMATICALLY TAKE THE SOME WORDS FROM FIGS AND MAKE IN PLURAL FORM , WHILE USING '' ARE'' LIKE BELOW
The fig is fresh - row 1
Figs are fresh - row 2
The Pomegranate is red - row 3
Pomegranates are red - row 4
=IF(EVEN(A1)=A1,"EVEN - do something","ODD - do something else") with iferron (for blank Cell)