Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I am currently taking Introduction to Image Interpretation online and there is a section in it that talks about Precision and Accuracy. I wanted to know if someone out there has any good information that I can use to learn more about it.

share|improve this question
6  
Is the Wikipedia article on the subject not enough? –  blah238 May 29 '12 at 19:23
5  
About three dozen threads on our site provide discussions of precision and accuracy in GIS applications. Use a search to find them. (Be a little careful, though: not everyone uses these two words correctly!) –  whuber May 29 '12 at 20:03
add comment

1 Answer 1

up vote 12 down vote accepted

Dartboard Precision vs. Accuracy

This illustration stuck with me, and helps me remember at the most basic level what precision vs. accuracy is.This is the source of the image, also containing a little more context. In general, Precision is the how close your grouping of measurements are. Accuracy is how close your measurement is to the actual measurement in the real world.

Blah238 is right, they left out Accurate, but not Precise - that might look something like: enter image description here

share|improve this answer
    
They forgot "good accuracy; poor precision" :) I guess you can't have good accuracy without good precision. –  blah238 May 29 '12 at 21:25
    
Nice catch! I added a poorly GIMP'ed image to illustrate that situation. –  Pixel May 29 '12 at 21:39
    
Nice one, thanks :) It's also noted in the Wikipedia article: Image –  blah238 May 29 '12 at 21:43
1  
Actually, the third image on the right illustrates good accuracy and low precision, because the centroid of the three darts is close to the center of the board. A correct illustration of poor accuracy and poor precision would show the dots widely scattered around a point far from the bull's-eye (e.g., they might be scattered around a point not even on the dartboard). A better source for these illustrations appears on our sister site, stats.stackexchange.com –  whuber May 30 '12 at 1:30
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.