# Arcpy handling of floating points

This arises from my own question How to handle coordinates accuracy in ArcGIS where I have tried to use the documentation entitled Using geometry objects with geoprocessing tools as a reference.

I have a table with coordinates in degrees:

I created event table and added it to the view with coordinates system 'GCS_NZGD_2000 WKID: 4167 Authority: EPSG'. I converted this single point to shapefile, defined it projection and computed coordinates of the point using 'Add Geometry Attributes' tool. This is resulting table with numbers as expected:

To replicate this in arcpy I've used this code:

`corners =[[174.73,-36.76]] p=[arcpy.PointGeometry(arcpy.Point(*coords)) for coords in corners] arcpy.CopyFeatures_management(p, "d:/rubbish/points.shp")`

I added output 'points.shp' to the view, defined projection and computed coordinates of the point using 'Add Geometry Attributes' tool. This is resulting table:

As one can see from the picture below the distance between 2 supposedly identical points is close to 10 meters:

However when I updated existing dataset **with defined projection** using

`infc =r'd:scratchfrom_xy.shp' outRows = arcpy.da.InsertCursor(infc,("[email protected]","X")) feat = (arcpy.Point(174.73,-36.76),0) outRows.insertRow(feat)`

It worked. Lessons:

- Don't use examples similar to the documentation entitled Using geometry objects with geoprocessing tools
- Define projection of dataset prior to any games with geometries.

**Does the documentation entitled Using geometry objects with geoprocessing tools need to be revised?**

As requested… posting my comment here

Use a spatial reference object, which I think pointgeometry supports, check the help. If a defined coordinate system is not used single precision is used in the calculations. References to this phenomenon are documented on this site and on geonet and a comment isn't the place to put them. No SR… =… inaccurate results - Dan Patterson 33 mins ago