Develop a app or a program to provide data from Pdf graphs

The software should be able to read graphs to generate a database. Then it would have to take certain inputs from user, and provide the final values that the user would have found from the graphs manually. For example, in the sample graph attached, X axis on the left graph has temperature and plotted lines on left side represent different pressure altitudes.
So for a given temp and altitude a point on Y axis is found. Now transferring this y axis point to the right hand side graph, for a given weight of the aircraft, total torque required from engine is found on the X axis (of the right hand graph) .

There are multiple such graphs, which need to be digitised and a collective app / software needs to be developed.