Classification of Hindu Temples
The exact birth of the history of temples cannot be traced exactly. The earliest temples were constructed of perishable materials like timber & clay. Next came the cave rock-cut structures. Elaborate structural temples with ornate architecture & sculpture came into existence much later.
The Gupta period marks the beginning of structural temples & a wide variety of styles were adopted. The temples were built of brick & stone. The Hindu temples can be broadly classified into three basic styles - Nagara, Vesara & Dravida according to the Silpasastras. The styles are not strictly restricted to particular regions. There is an intermingling of styles, but it can be broadly considered that a particular style was more prominent in a specific region. (Northern, Deccani, Southern styles).
The construction of a temple is a religious act, thus great care is taken to ensure that all rules & conditions laid down are adhered to strictly, starting from the land selected for the temple. The location has to be appropriate in the sense that it should be a clean, serene place to invoke peace.
For all power to get concentrated in the vigraham, the norms as laid down has to be followed in every step. None of these rules are the whims of our ancestors, but based on hard scientific facts. The vigraha also has to be made according to specifications. The main deity is housed in the garbagriham & there are Utsava murthis made of bronze.