In version 5.25 “Mean” option added in Main Menu>Tools>Option>Magic Selection/Color Bucket Settings…. Enabling this option makes area always same and accurate at a particular tolerance, even in noisy environment and clicking anywhere in a region. You will get this image in “Trial Images” folder to test yourself.
Accurate measurement with Measurement palette
For accurate map measurement the selection have to go through the center of the map border. But if your map border is thick then you have to grow the selection for setting it through the center line of the border. By measurement palette you can grow or shrink the selection separately width or height or both and you will get the area, width, height of stretched selection same time.
For example, if your border is 2px thick and after selection and clearing noise width is 129px in Result palette. Then new width in measurement palette have to be 130px. If you are measuring map then don’t forget to enable the “Calculate with border” option.
Accuracy comparing of Whoitam Image Measurement with other internet resource
Whoitam Image Measurement is accurate than any other software in internet up to now. You see it in this video. It is only an example. Here a script is used to draw the circle to test. Because, circle drawn by this method makes more accurate shape than other circle drawing method. you will find this script in “Script Samples” folder.
Adjusting area when drawing map
Clear Noise
Calculate with border
Length through border
How does Whoitam Image Measurement measure and use calibration
It gets the DPI settings from scanned image to know real one inch on paper equal how many pixels on image. The DPI settings come from scanner and recorded in image file. For example, an image may be of 1,000 × 1,000 pixels. If it is labeled as 250 DPI, that is an instruction to Whoitam Image Measurement to measure it at a size of 4 × 4 inches. So, Whoitam Image Measurement can determine real one inch on scanned image by DPI. If you put real one inch of paper equal what is in your unit in real world as calibration, it will show the area or length in real world units (feet, mile, kilometer, decimal etc). So, just scan and open in Whoitam Image Measurement, because most of the image editors destroy the original DPI settings from scanner. If your image is not scanned then you have to put manual calibration and in this case see our “Measuring length and Angles in Degrees in an image using Whoitam Image Measurement” post.