Map Co-Ordinates not appearing when using st.map(df)

Greetings,
I was just experimenting with the st.map(df) and I was not getting the expected result. I just get a blank without any points being plotted. Requesting the community to guide me.
I have implemented the following:
I have already taken the dataframe input using file_uploader

try:
                        lat= st.selectbox("Select Latitudes column " , df.columns, key="8")
                        long=st.selectbox("Select Longitudes column " , df.columns, key="9")
                        d={"lat":df[lat],"lon":df[long]}
                        temp=pd.DataFrame(d,columns=['lat', 'lon'])
                        st.map(temp)
                    except (ValueError,TypeError):
                        st.error("The selected column is not in a Co-Ordinates format. Please Select a valid Column.")