GPS issues must rank in the top 5 subjects in the Equipment sub-forum at Stormtrack. Accordingly, I thought it would be a good idea to have a "one-stop shop" that could answer most of the common questions people would have. I know that we have several GPS-savvy folks on here (Mark Blue comes to mind), and I invite anyone to add anything of value to the thread. Let's get started! Why do I need a GPS? 1. Mapping purposes - Many chasers carry a laptop with them and run apps like Delorme Street Atlas or Microsoft Streets & Trips. Using a GPS receiver with these apps allows for you to determine your position on a map, along with being able to keep track of route/distance travelled, current direction/speed, distance to waypoints etc. 2. Weather Apps - Popular applications like GRLevel3, StormLab and others can ingest GPS data to allow the user to see their position in relationship to weather features on a map. Other specialized apps can use GPS data too: SpotterNetwork for instance can take your GPS data and use it to indicate your position to the NWS or other interested persons. What kind of GPS do I need to buy? This is one of the most confusing aspects, mostly because GPS technology is being incorporated into many devices. Be aware that only certain GPS devices are suitable for a broad-range of chaser/spotter applications. Specifically, the device needs to be able to output GPS data in a useful format; most often this will be NMEA 0183. Most GPS-enabled software applications will be looking for GPS data in this format. Here's a breakdown of GPS units you are likely to encounter, and their suitability: "Car Navigation" GPS units - Not suitable. Most of these units do not output GPS data of any kind; they are intended to be used as standalone units only. In some cases they can be "hacked" to provide data, however this appears to be quirky and/or risky in the least. Accordingly I do not recommend them for anything other than standalone use. Handheld "hiking" units - Possibly suitable. Many of these units will output NMEA format data, however this is often only via a serial-port which can be problematic to deal with. GPS "Pucks" - Most suitable, especially the USB versions. These are easy to connect and use for most applications. Please ensure the version you select can output NMEA 0183 data; see the next message in this thread for some recommendations. How do I connect the GPS to my computer? Serial-Port - GPS data was traditionally communicated via a serial-port (R2-232), however Laptop manufacturers in particular have removed this connector to save money. Most older GPS units will use this type of connection on them (some current GPS units on the market still do). In order to use a GPS unit with a serial-port type connection, you will need a Serial-USB type adaptor. Be aware that these are getting scarce to find, and can be troublesome to setup. Best advice is to avoid any GPS unit that only uses a serial-port unless you have a working solution for it. USB - Newer GPS devices will generally use USB. Be aware that just because a GPS device has a USB connector on it, doesn't mean it can output GPS data (i.e. Tom Tom's etc). It's interesting to note that in most cases, NMEA formatted data that is sent via a USB connection will usually be converted to a "virtual serial port" using software that comes with the device. Please note that most USB connected GPS receivers will require a specific driver to be installed; please consult documention prior to connecting the device to your computer. Bluetooth - this technology can also be used for the connection. A few GPS "pucks" use this feature, which can be handy since you can have a completely cordless solution for your GPS and keep things tidy. Once again, specific drivers are often needed and the setup can be somewhat complex initially (experiences vary on this). Once again I would personally recommend a USB-connected "GPS Puck" for most applications since it's the easiest and most economical method to get GPS data into your computer. Recommended models are included in the follow-on message. Can I use a single GPS receiver for multiple applications? Yes! You will need additional software for this however. The initial problem is that the GPS data is normally being interfaced into a single "virtual serial port". Normally only one application/device can use a serial-port at a time. Luckilly, "GPS-splitting" software has been around for a number of years now. These appplications will create additional "virtual serial ports" and will permit your GPS receiver to be shared among several applications. The two main applications for doing this are: GPSGate - Appears to be used by the bulk of chasers. 14-Day trial, $39.95 for "Standard Version". Includes many features, including ability to convert "Garmin" format data into NMEA 0183. Also works very well for some Bluetooth type GPS units. XPort - Freeware (donations glady accepted). Used succesfully by several chasers (including myself). Currently only works reliably on 32-bit Windows platforms. Can I connect my GPS to my <insert device here>? There's all kinds of new scenarios coming up for GPS technology, including unconventional ways to use the data. I would suggest that if you have a specific question on GPS connectivity that you ask it here; perhaps somebody who's done this already can chime in and help out. Some immediate examples of this could include how to connect a GPS unit to an iPad or Android-based tablet. In the next message I list a number of GPS units that I've researched, and their applicability for chasing. Good luck!