How can I convert x,y,z (easting, northing and elevation) data into station and elevation? I am trying to input the data into HEC-RAS, which only takes station and elevation.
When using HEC-RAS, River Stations always start with Station 0 the farthest DOWNSTREAM (lowest elevation along that river reach), and are 'numbered' upwards in the upstream direction.
You need to make sure that you are only working with stations from 1 unique river. Once you have all the stations from one river, you can input them from lowest elevation to highest. You will not need to look at the E/N coordinates at all. I am of course assuming all your points fall along rivers!
To reiterate, class your data by river reach, and then for each class, order lowest elev to highest. Input in that order, by each class.
This might be too late but just in case it can help someone else with the same question. The image below shows the plan view of a cross section, defined by four points, p1 through p4, with p1 being the starting point. Since in HEC-RAS XS station is measured from the starting point along the cross section, for P1 you enter it as (0, z1). P2 will be entered as (L1, z2) where L1 is the distance between P2 and P1 and can be calculate as the square root of (y2-y1)^2 + (x2-x1)^2. P3 will be entered as (L1+L2, z3), where L2 is the distance between P3 and P2 and can be calculated as the square root of (y3-y2)^2 + (x3-x2)^2. So on and so forth. Hopefully you can find a tool on the internet that does the conversion so you don't have to do it manually.