# Distance Interpolation using Mile Posts on a Rail Road's Center-line

Discussion created by ramsinc_maps on Oct 3, 2019

I have fought with this task for quite sometime now and have finally decided to release myself of the anxiety that I may not come up with the answer I need before I get recommended for Janitorial duty at my company. I have an advanced license in Arcgis Pro/Desktop: I have to take all of our client's Railroad Centerline (One, Single, Continuous Line, that I have created as a SHAPEFILE/LINE in the desktop's software, and "Interpolate" distances between certain "Mile Post Numbers (MP)." In the older days these MP's were measured "BY COUNTING STEPS" at 1 mile intervals along said Railroad track (Our Centerline). Using today's technology, I can see that each Mile Post Marker (MP), at "1 mile intervals" along this track, has a different measurement value of distance because of the way they stepped the miles out. Sometimes 1.3 miles, sometimes 0.75 miles (Ex. Mp 64.00 is 1.3 miles away from MP 65.00 while at the same time MP 63.00 is 0.75 miles away from MP 64.00). I NEED TO TAKE THAT RR CENTERLINE THAT I CREATED, ADD THE "KNOWN MILE POST MARKERS" WE FOUND IN THE FIELD TO THAT "RR CENTER LINE" THAT I CREATED AS A REFERENCE, THEN SEGMENT/INTERPOLATE THE DISTANCE BETWEEN EACH MILE POST MARKER SO THAT EACH 1 MILE SEGMENT CAN BE BROKEN DOWN INTO 0.02 FRACTIONS/DISTANCE MILES (REGARDLESS OF HOW FAR THEY TRULY ARE IN REAL LIFE (i.e. 1.3 miles shown as 1 mile). AFTER SEGMENTING THE LINE INTO FRACTIONS OF DISTANCE, I CAN THEN REFERENCE ALL POINTS AND ROAD CROSSINGS TO AUTOMATICALLY FILL IN THE APPROPRIATE DISTANCES (MP NUMBERS) BECAUSE THEY DO NOT HAVE THAT DATA . I NEED TO INTERPOLATE EACH 1 MILE MP TO MP MARKER SEGMENT SO I CAN USE THE LINE FOR THE MP DATA REFERENCE LATER.....SO BASICALLY I NEED MP 64-65 TO READ 64.00, .02 .04 .06 .08, AND THEN MP 65.00 ALL OF WHICH WILL BE ON THE RR'S CENTER-LINE ITSELF (OUR DISTANCE REFERENCING LINE). I HAVE TRIED USING PERCENTAGES INSTEAD OF DISTANCE IN THE "GENERATE POINTS ALONG LINE" GEO-PROCESSING TOOL. I KEEP COMING UP SHORT. I ALSO TRIED EXPORTING THE GENERATED "POINTS ALONG LINE" AND INTERPOLATING THE DISTANCES IN EXCEL BUT IT WAS NOT ACCURATE.