If your event is easy to find or you have someone who can create a detailed map you may not need any written instructions for finding your ceremony and reception site. In this case you can go with a simple map card.
Map cards can be used in conjunction with direction cards if you location is difficult to reach or your events are complicated.
You want to be sure that your instructions are clear and error free. A map card that has been poorly assembled or proofed can sour the day for everyone. This card is often where accommodation and local activity information is included. More casual events and folks who are looking to reduce paper usage will include phone and email response requests on this card too.