Custom geocoding in Tableau - Cell-by-Cell Formula Trace

Sample Data

This data represents a small custom geocoding table with city names and their latitude and longitude coordinates.

Cell	Value
A1	City
A2	Springfield
A3	Rivertown
A4	Lakeside
B1	Latitude
B2	39.78
B3	40.12
B4	38.95
C1	Longitude
C2	-89.64
C3	-88.45
C4	-90.12

Formula Trace

IF [City] = 'Springfield' THEN MAKEPOINT(39.78, -89.64) ELSEIF [City] = 'Rivertown' THEN MAKEPOINT(40.12, -88.45) ELSEIF [City] = 'Lakeside' THEN MAKEPOINT(38.95, -90.12) ELSE NULL END

Step 1: [City] = 'Springfield'

Step 2: MAKEPOINT(39.78, -89.64)

Step 3: [City] = 'Rivertown'

Step 4: MAKEPOINT(40.12, -88.45)

Step 5: [City] = 'Lakeside'

Step 6: MAKEPOINT(38.95, -90.12)

Step 7: ELSE NULL

Step 8: Complete IF statement evaluation per row

Cell Reference Map

    A          B          C
1 | City     | Latitude | Longitude |
2 | Springfield -> 39.78 -> -89.64 |
3 | Rivertown  -> 40.12 -> -88.45 |
4 | Lakeside   -> 38.95 -> -90.12 |

The formula uses the City names in column A to match and assign latitude and longitude from columns B and C.

Result

    A          D
1 | City     | Geo Point            |
2 | Springfield | (39.78, -89.64)    |
3 | Rivertown  | (40.12, -88.45)     |
4 | Lakeside   | (38.95, -90.12)     |

The result column D shows the geographic points created by the custom geocoding formula for each city.

Sheet Trace Quiz - 3 Questions

What does the MAKEPOINT function do in this formula?

A Returns NULL if city is unknown

B Checks if the city name matches

C Creates a geographic point from latitude and longitude

D Calculates distance between two points

Key Result

IF city name matches a known city THEN create geographic point with its latitude and longitude ELSE return NULL