Matching point data with non-traditional coordinate system to shapefile with coordinate system?

Question

I'm working with in-situ data collected from several field sites that must be converted into points that lie within a separate layer of polygons. These polygons are the boundaries of the different study areas, in which the points, representing trees, must go. I've successfully converted the in-situ data to points, but I'm having a lot of trouble making those points fall within the necessary polygons.

The issue is that the point data does not have a traditional coordinate system. We based our coordinate measurements off of a 30x30m plot, and the points correlate to a 30x30m grid. As a result, even if I ensure that the coordinate system matches, the points are very spread out in ArcMap - to the point where I can't drag and drop them to the correct spot on the polygons because they're impossible to find unless I zoom to the layer.

Is there a way for me to define a lat/long extent for the point layer that matches the lat/long extent for the polygons so that I can make the points within the boundary of their respective polygons?

I'm relatively new to ArcGIS.

Answer 1

The points are spread out or dislocated? If I fully understand you, if the point shapefile and the grid match but it just seems spread/spaced out, it seems to me that your problem (the spacing-out) is most likely related to the symbology chosen for your point shapefile instead of it being inaccurate, because coordinate problems happen in a systemic way, meaning that all the points would be moved to a certain direction and/or the distance between them will different then it should be. To make sure that you are really facing a coordinate problem, I'd suggest you measure the distance between points and see if it's completely unreal (I'm assuming you have such information or, at least a distance notion precise enough). If the distances are accurate, then try changing the symbology and choose bigger dots to see if the spacing-out impression disappears.

Please note that dragging your data will remove the precision on which it was collected in every circumstance. It is always preferable to fix the problem on a different way.

Another thing that I should ask you is how this data was collected and what did you mean by unusual coordinate system. Arcmap converts the data you input on-the-fly and if you used a GPS, then I doubt the coordinate system is unknown to the software.