Why is Ahmedabad called rajnagari

The context includes references to historical and cultural works about Ahmedabad, such as "Amdavad na Sthapanano Samay" by Hariprasad G Shastri, which discusses the founding period of Ahmedabad, and "Ahmedabad Shaher Yatra" by Bhavyanandvijay, which explores the city's spiritual and cultural journey from a Jain perspective. However, none of these sources explicitly address the reason behind the title "rajnagari" (meaning "royal city") for Ahmedabad. Without direct information or historical explanation in the provided texts, it is not possible to accurately state why Ahmedabad is called rajnagari based on this context.