Visualize geographical data with grafana geomap panel

I have a grafana instance which receives data from a influx-bucket. Within this data i have Latitude and Longitude values for my sensors. And a value which provides every measured value by this sensor.

First of all i wanted to ask if its smart to label longitude and latitude as a _field inside my influx-db-bucket or if it is smarter to label them as another tag ?

The second question would be on how i could query them (flux-language) so that i will see them inside my grafana geomap panel.

from the web:

InfluxDB lets you specify fields and tags, both being key/value pairs where the difference is that tags are automatically indexed.

Because fields are not being indexed at all, on every query where InfluxDB is asked to find a specified field, it needs to sequentially scan every value of the field column.

For flux go here