From Longman Dictionary of Contemporary Englishhave/get the measure of somethinghave/get the measure of somethingJUDGEto become familiar with something, so that you can control or deal with it → measure
Examples from the Corpus
have/get the measure of something• He may have the measure of the John Gosden-trained Anshan, running from stall 15.• Booth and Rowntree were more concerned with getting the measure of poverty than with trying to devise a general theory about it. 