Sizing images to the size of an object within an image - Indesign

Question

I want to know if there is a way to size an image with a specific part of the image being a specific size. Like let's say there is a line on my image that I want to place, I want the line within the image to be 2cm... hope you know what I am asking! Help would be much appreciated, as I have a huge number of images (all different sizes, and resolutions, but always need a specific part of each image to be the same size) So it would basically be perfect to tell InDesign by measuring said area to size it to (f.e.) 2cm.

At the moment I am just making an object in the required size and scale my images accordingly, but it's a bit of an inexact way of doing it...

Answer 1

Really, the only way to do this is by ensuring the images themselves contain the correct size object, then when you link to the images in InDesign, you would ensure all images are the same scale.

For example, you draw a 2CM line in Adobe Illustrator and save it as a .ai file. You place that .ai file into an InDesign layout. As long as the linked image is at 100%, the line will be 2cm.

Internally InDesign has no way to measure object within a linked image file. It sees the bounding area of the image (as defined upon import), not the pieces.