Obtain the estimated value from GeoDensityPlot or GeoContourPlot?

I want to know the estimated value of Specific location (for example, University of Chicago GPS: 41.788056, -87.599518), what should I do?

The following are examples provided in the documentation.

GeoDensityPlot[Table[lat, {lat, 0, 90}, {lon, 0, 180}], 
 DataRange -> {GeoPosition[{0, 0}], GeoPosition[{90, 180}]}]