Units

 

Free Your Mind

Free your mind
And the rest will follow
Be color-blind
Don't be so shallow

Get the UNITS right, and the rest will follow.

When I was in High School, more years ago than I care to admit, my chemistry teacher gave some advice that I have found to be very, very wise.  When you are doing anything, especially trying to solve chemical formulas, get the units correct and the correct solution will be much easier. 

I have seen so many people struggle when they ignore this rule. 

• If something is supposed to be dimensionless, then you better have the same units on top in the numerator as you have on the bottom in the denominator.  
• When you are using stored numbers, the instructions (metadata) will have the units.  
• If something is stored in hundredweights, remember to divide by one hundred if necessary.  In addition to the units, the instructions might also include how many digits are stored (e.g. in thousands, in millions, etc.).  
• A number might, for example, be for longitudes and even though a positive number is stored, all of the longitudes might all be in the western hemisphere and by convention that longitude might have an implied negative sign.  
• A blank may look like no data, but a computer program may see a difference between a blank, a text null, a text zero and a numeric zero, even if they might all mean no data to you.  
• A spoonful of sugar is not just a Mary Poppins song. If it is a TEAspoon of sugar then it is a measurement that is different than a TABLEspoon of sugar.  

If something is a measurement, know the units, and the rest will follow.