Adding X, Y coordinates in a table to ArcMap

Coordinate Conversion

The coordinates below are spot locations for 3 campus buildings.  Using the DOQ of the campus (csuf.tif), please identify the buildings from the coordinate pairs listed below.

If you don't know the names of campus buildings, look at these maps for help

Note:  Some versions of ArcMap (and other software) do not easily accommodate coordinates in degrees, minutes, and seconds.  You should convert these locations to decimal degrees before creating your ArcMap table.

1          N 33° 52' 44.08"    W 117° 53' 4.60"

2          N 33° 52' 54.64"    W 117° 53' 12.62"

3          N 33° 53' 1.09"    W 117° 52' 59.76"

Adding Events

There are a variety of occasions where you might encounter point data in a tabular format.  ArcMap calls these point locations "events."  In order to add these events to a Data Frame, you must create a table containing the X and Y coordinates in separate columns.  The following instructions guide you through the creation of a new table and then adding points from the table to a Data Frame.  

You will create a new table in ArcCatalog. ArcCatalog is the application within ArcGIS that allows you to browse, organize, and document your data. This is also where you create new empty tables or shapefiles.

• Open the Catalog window by pressing the Catalog window button on the menu
• Click the + next to Folder Connections
• If you do not see C:\temp, click the Connect to Folder button and browse to it..
• Right-click on the c:\temp directory
• Select New - dBASE Table
• Name the new table buildings.dbf you must do this in ArcCatalog, not the TOC
• Exit ArcCatalog
  

While you can add your new table to any data frame to complete the remaining steps, I find it easiest to add the table to a new, empty data frame.

Whichever way you choose to add your table, open it. It should be empty except for two system variables.

Time to add some data:

• Add the following field with the designated parameters
  • Name - Latitude
  • Type - Double
  • Precision - 10
  • Scale - 6

Repeat the process to add a Longitude field with the same parameters

Now you will add three new records to your table

• Open the Editor Toolbar by pressing the Editor Toolbar button on the menu.
• On the Editor Toolbar Click Editor - Start Editing
• Notice that a record has been added to your table
• Double-click in the cell under the Latitude Field name and enter your data
• Notice that a new record has been added. New records will be added as you continue to enter your data
• Add the appropriate Longitude data and proceed to the next record
• When you have added all three of your points (events), return to the Editor Toolbar and Click Editor - Stop Editing
• Press Yes when asked if you wish to save your edits.

You may experience the same bug as mentioned in the Heads-up digitizing hand out.

Now you are ready to add the event table to your data frame as an event layer.

• Right click on the table in the TOC and click Display XY Data
• Make certain your new table appears in the choose table drop-down box
• X Field – The field in the table that contains the X-coordinate or longitude data.
• Y Field - The field in the table that contains the Y coordinate or latitude data.

Press OK to add the event source to the data frame.

Note:  If you wish to select a field in the table but are unable to see the field in the drop-down list, it is possible that the field has been hidden or renamed with an alias. In any case, you can open the Table Properties Dialogue Box to reveal the field and make it visible.

Attention:  It is important to realize that, although you are viewing the point locations as a layer, they are not in Shapefile format.  It is useful to right-click the event layer and click Data - Export Data and save the locations as a new Shapefile.  This eliminates any of the idiosyncrasies you might otherwise encounter when working with event layers.

This new shapefile does not have a defined projection, so...

Defining the Projection

ArcGIS can have trouble with unprojected and undefined data so you will have to define the projection for your shapefile of building events. You may also need to do the same for your GPS landmarks, as well. A detailed explanation of the Define Projection Tool is available here.

Use the Define Projection Tool as follows:

• Double-click Geographic Coordinate Systems
• Double-click World
• Highlight WGS 1984
• Press OK twice
• Close the Define Projection dialog if necessay when processing has been completed

The XY coordinates you added from the table and exported as a shapefile will now have their projection defined and should work with your other data.

Adding the Building Name Field

Once you have identified the buildings, modify the attribute table for the shapefile you created to include a field with the building names.

Last modified 10/26/2021