# Offset Coordinates

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07-11-2016 01:45 PM
New Contributor

I have an excel file that has XY data in state plane format.  The coordinates were taken from a survey plat and each coordinate has its own offset value.  Is there an easy way or a tool that I can use that will shift the coordinates to their actual location after the offset is applied?

Thank you!

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11 Replies
MVP Honored Contributor

Can you provide a simple example of your data? I'm imagining you could add two new columns to your Excel file, calculate the new coordinates into the new columns using x,y offset values from other columns, and plot your plots using those coordinates, but that seems too easy...

New Contributor

The data has been attached to the post.  Thank you for taking a look at it.

MVP Honored Contributor

That dataset only has one offset value. Do you have any more information? Simple situation that shows this doesn't work, as is: you're standing at (0,0). I tell you to "Move 10". Where do you go? You need more numbers, or more rules.

New Contributor

I do not have any more information.  The table on the original survey plat only shows what I have provided and then a station value such as 1700+530.387.

MVP Honored Contributor

It appears as though your points are in reference to some other line (like I've guessed below, negative offsets blue, positive offsets red). Are you trying to move those points to their position on the line, or what is the objective?

New Contributor

Most of the locations are "found iron pins" along the roadway you see on the map to the west of the line you have drawn.  Once I have the dots in the correct location I can georeference in an image from the survey plat so that I can get the location of easements and right of way boundaries.

MVP Honored Contributor

If I understand correctly, your point coordinates are "correct" for some coordinate reference system slightly different from State Plane Meters, like there is an offset of 30m or so (as I've mapped above). The offset value in your spreadsheet corresponds to the offset from the road center, where zero would be the center of the road. Unfortunately, as they are, the coordinates don't correspond to the road in terms of regular State Plane Meters. Does your survey plan give any other hints about the coordinate reference system?

New Contributor

No it does not.

Regular Contributor II