Should I use prometheus or influxdb
Prometheus is a time-series database. The question is, do you need more data types and a stronger query language? What type of data is saved for location? Geo coordinates? 

It also depends on your availability requirements. Both InfluxDB and Prometheus are single node. InfluxDB supports clustering only if you purchase the enterprise version. 

For Prometheus, you need multiple instances to ensure high availability and they will be scraping the same data in duplicate. If your data requirements are high, you may have to look into long term remote storage. https://prometheus.io/docs/prometheus/latest/storage/#remote-storage-integrations. 

We have developed a new serverless time-series database as a service called Hyprcubd. Full disclosure, I’m the founder.  It was architected with IoT in mind. It supports multiple data types, long term storage, and high availability. https://www.hyprcubd.com