the LatLng function expects both arguments to be a number:
new google.maps.LatLng(-34.397, 150.644)
So yes, you do need to do a conversion first. Check the documentation:
- Latitude ranges between -90 and 90 degrees, inclusive. Values above or below this range will be clamped to the nearest value within this range. For example, specifying a latitude of 100 will set the value to 90.
- Longitude ranges between -180 and 180 degrees, inclusive. Values above or below this range will be wrapped such that they fall within the range [-180, 180). For example, 480, 840 and 1200 will all be wrapped to 120 degrees.
and see this sample