Thingworx doesn't have the ability to have tooltip pop ups when you hover over areas of an image, but there is a possible work around. Create a static mashup and set the background image of the mashup to the image of the map. You can then place navigation widgets on top of the areas where the sensors are located. Create a mashup that has the data you need displayed and set this to the Navigation widget's Mashup input parameter. Just remove all styles from the navigation widget and all text and it will be invisible, but still clickable. Set widget to pop up in the widget configuration and when you click on the sensor location, a pop up will appear with the data you want to view.