Is it necessary to call the Adhan and Iqamah for someone praying alone because there is no mosque nearby?

The Sunnah (definition) is to call the Adhan (definition) and Iqamah (definition). Whether it is obligatory is a matter of scholarly disagreement. The more cautious approach is to call the Adhan and Iqamah due to the generality of the evidence. You must pray in congregation whenever possible. So, if you hear the call to prayer from a nearby mosque or find a congregation, it is obligatory for you to respond and attend. However, if you do not hear the call to prayer and there is no nearby mosque, then the Sunnah is for you to call the Adhan and Iqamah yourself.