Arduino shield stacking

Projects General Guidance
1

I am working on a GPS project where currently I have

  1. UNO board
  2. Arduino GSM Shield

I need to buy a GPS receiver. I have two option

  1. GPS Shield Retail Kit - RTL-10709 - SparkFun Electronics
  2. http://www.cooking-hacks.com/gps-module-for-arduino

My question is,

  1. Can I stack GPS shield above Arduino GSM shield as Arduino GSM shield already placed in UNO board ? Will It work ? I saw the I/O pin configuration and confused in stacking one above the other.

  2. Is there any alternatives to the GPS shields other than the mentioned links.

Thanks in advance.

2

A shield, by definition, is stackable and, if it looks like a shield, it's a shield. A module isn't stackable but may be made part of the stacking system by being incorporated into a shield. Alternatively, it may be connected to a shield or directly to Arduino by flying leads. Any pin configuration issues can usually be fixed by jumpers or patches. The only limit to stacking is the power supply, but three or four levels is common.