This a simple tutorial one can follow to define (overwrite) or reproject (transform) a Coordinate Reference System (CRS) in ArcGIS 10.1+ starting from a CSV file. To clearly understand 'define' and 'reproject' concepts refer to this answer.
File --> Add Data --> Add XY Data;
Browse the CSV file which contains column
A with longitude (or Easting) values; and column
B with latitude (or Northing) values. Example:
3.1. Select column A as the
X field and column B as the
Y field from the CSV file;
Coordinate System of Input Coordinates field, select current CRS from data (or choose one manually).
Here the CRS is defined. One can export the layer to a shapefile by right clicking in the layer and then,
Data --> Export Data.
Or continue (from item
3.2) to reproject:
- Click on
ArcToolBox button (little red toolbox icon), then go through
DataManagementTools --> Projections and Transformations --> Feature --> Project;
4.1. Select the input layer from the
Input Dataset or Feature Class field;
Output Coordinate System choose the CRS one wants data to be projected (transformed) to.
4.3. Set file path and name for the output file in
Output Dataset or Feature Class field.
Ok and wait while
Project finish running.
Here data is already reprojected to new CRS.
Now, let's create columns with new
Y coordinates in the layer's table of attributes:
- Right click the new created layer and select
Open Attribute Table;
5.1. Click on
Table Options (upper left corner), then
Add field to add new
5.2. Chose a name for the column (e.g.
X_coords) and set the
Type field as
5.3. Repeat steps (
5.2) for creating column
- Go back to the Attribute Table and right click
Calculate Geometry. Set
X coordinate of Point. Verify if
Use coordinate system of the data source is selected. Click
6.2. Repeat steps
6.1 for column
Y_coords, but select
Y coordinate of Point instead.