You can change the measurement units for all geospatial PDFs in the Preferences dialog box. Click Measuring (Geo) from the Categories section.

Enable Measurement Markup
This tool enables you to add a label to a geospatial measurement. When Enable Measurement Markup is selected, choose Use Label, and then type a label for measurements.

Snap Settings
Select the path parts to which you want measurements to snap to.

Display Value As
Determines how latitude and longitude values are calculated. Choose Decimal to display latitude and longitude as a decimal fraction. Choose Degrees, Minutes, Seconds to divide each degree of longitude into 60 minutes, each of which is divided into 60 seconds.

Display Direction As
Choose between Signed and Named. Named direction displays an N (north) or S (south) next to the Latitude, and an E (east) and W (west) for Longitude.

Always Display Latitude And Longitude As WGS 1984
Select to ensure that latitude and longitude use the currentm standard reference frame for earth (World Geodetic System 1984). For older maps that were drawn with an earlier grid (such as NAD 1927), you can deselect this option to see the original values. When an older map is registered in its native coordinates, coordinate positions can be different from current standards used in GPS devices and web mapping services.

Use Default Distance Unit
Select the measurement unit to use.

Use Default Area Unit
Area can be measured using a different unit from distance.

Don’t Show Transparency Layer In GeoTIFF And JPEG 2000 Images
Raster image formats include a transparency layer that you can choose to remove.