>We have a Trimble GPS and I want data from it. From a cable connected to COM1 I can read NMEA data using a terminal program. I want to read using MSComm32 but couldn't succeed yet. Has anyone done it ? TIA.
>Cetin

Hi Cetin,

I've been using a Garmin GPS for a few years, and I've experimented with using VFP to manage GPS data. Sorry I can't help you at the MSComm32 level, though, because I rely on a crude DOS-based program (PCX5.COM, supplied by Garmin) for uploading and downloading data from the unit.

The PCX5 software can read and write a simple ASCII representation of data for waypoints, routes, and track logs, making it relatively easy to import and export GPS data in and out of my custom VFP application. It would be nice to have a cleaner, more straightforward way to programmatically upload and download the GPS unit, so I'd be interested to know what you come up with for doing that.

My Garmin GPS12XL unit supports a proprietary Garmin communications interface and several versions of NMEA. For uploading and downloading, I use the Garmin-to-Garmin setting, but for live tracking I use NMEA-to-NMEA. My guess is that there are quite a few device dependencies to contend with across different makes of GPS equipment, even between different models from the same vendor. This suggests that it would be sensible to have a generic, modular component that deals purely with programmatically getting data in and out of GPS units in a standardized, device-independent manner. I don't know if such an application/library exists, but if it did, I'd be a potential customer.

My own interest in GPS has been mainly as a hobby, but I also see it as a juicy potential product area where VFP could play a central role. I just spent the past few days harvesting more GPS data in the woods of Vermont. Even with the government's removal of "selective availability" (a classic euphemism), I find it necessary to do a fair amount of massaging to get sufficient accuracy. By recording track logs at various fixed locations, I can continually refine my estimates of the exact coordinates of points of interest. Then I plot these points on a digitized USGS map (obtained from Landinfo). This sort of fine-grained mapping and GPS data management application seems like something that could marketed to many rural property owners, surveyors, outdoor types, etc.

I did make a few inquiries a while back with Landinfo International, to see if they might be interested in sponsoring some product development along those lines. They were somewhat interested, but not enough to inspire me to persue this product idea very far before I got diverted into something else. In any case, it's been a great excuse to be hiking in the woods instead of sitting in front of my computer!

Mike