gijung Posted July 30, 2013 Report Share Posted July 30, 2013 Hey guys, so I am using Photoshop to measure some things for my extended essay with the ruler tool.However, I have been trying to think how to get the uncertainty of the tool as I need it to make the calculations and analyze the data. I have sent an email to my supervisor yet he has not responded me and even searched on the internet hoping that I would get some kind of idea or guide that would help me figure it out.... but nothing, and I have my draft due in a week! I hope any of you guys know anything about this! and if not, thanks anyways! ^^ Reply Link to post Share on other sites More sharing options...
theboro76 Posted July 31, 2013 Report Share Posted July 31, 2013 Im not sure exactly what the ruler tool on photoshop is, however, a ggod rule of humb is that the uncertaintity is either, the smallest digit, if the equpitment is digital, or 1/2 the smallest measurement if the equiptment is analogue.For the photo shop tool, I assue it gives you a figure, as opposed to having an actual virtual ruler picture. If this is the case then the uncertaintity is the smallest digit. e.g. if you get a reading of 1.768cm, the uncertaintity is +/-0.001cm. or if the reading is 1.8cm, the uncertaintity is +/-0.1cm Reply Link to post Share on other sites More sharing options...
gijung Posted July 31, 2013 Author Report Share Posted July 31, 2013 For the photo shop tool, I assue it gives you a figure, as opposed to having an actual virtual ruler picture.The reason I am not sure is that, although it is "digital", I still have to define the boundaries (as in, I have to give the program where is the beginning and where is the end), which, in my opinion, kind of makes it into an analog instrument. Reply Link to post Share on other sites More sharing options...
theboro76 Posted August 1, 2013 Report Share Posted August 1, 2013 I'd go with twice the lowest digit then. .001 for the lower bound and .001 for the upper bound therefore .002. (assuming it measures to 3dp). Does this make sence to you. I assume some one more experienced can confirm 1 Reply Link to post Share on other sites More sharing options...
gijung Posted August 1, 2013 Author Report Share Posted August 1, 2013 that makes sense! Thank you so much for your help! ^^ Reply Link to post Share on other sites More sharing options...
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