Does anyone on this forum have experience with using GPS on Palms and are there any problems using GPS in respect of memory capacity or the Palm operating system?

I have recently received some publicity material for the Handspring Visor, a new palm clone. Does anyone have experience with this device?

I could just go for the model with the cool interchangeable fascias but I suppose I should investigate functionality a little further.

Thanks
Mike Ellison

Reply to post by Mike Ellison, on June 21, 2000 at 13:48:29:

I've been researching this topic, GPS on Palms. The problem seems to be getting useable maps downloaded from my Mac to the Palm. Garvin makes some units that apparently work well. Not sure yet what the memory load is. Shold be relatively small for the software, but the maps will take up some space.

Reply to post by Mike Ellison, on June 21, 2000 at 13:48:29:

Delorme, the makers of Street Atlas map software, have an application called Solus Pro that allows Windows users to upload maps to the Palm. You can then use the Palm application to connect to their own Earthmate GPS receiver, or other brands. Check their site at www.delorme.com

Reply to post by Mike Ellison, on June 21, 2000 at 13:48:29:

One of the supposed advantages of the Handspring Visor (Palm clone) is that the Springboard expansion slot allows for add on devices and modules.... on of the suggested ones being a GPS module. It would be a third party device, I don't know if anyone has offered it yet.

Reply to post by Mike Ellison, on June 21, 2000 at 13:48:29:

What are the advantages of GPS linked data collection? Is it on the back end because e.g. GPS units (rather than street addresses) to are used to route crews? Research has shown that unless the GPS provides sub-meter accuracy, if you have good base mapping data collectors can spot trees on those maps more accuarately than the GPS, probably at lower cost/tree. (The street line is here, the curb cut for driveway is here, the fire hydrant is there, the utility pole is there and the building is there, so that tree's about here.... dot on map.) Up till now equipment capable of sub-meter accuracy was quite expensive and also dependent on sattelite times/tracks (sometimes you get it someties you don't). A related question is whether the recent de-scrambling of the GPS satellite signals for non-military users gives sub-meter accuracy to consumer grade GPS electronics.

Reply to post by Russ Carlson, on June 21, 2000 at 13:48:29:

Scott:

Re the accuracy issue. Even with the unscrambling now in effect, there is a vast difference in accuracy between the high end and low end models. We use a Trimble Pro XR which is definately high end, but allows sub metre accuracy in a wide array of conditions including under forest canopy. I was out on Friday locating potential development sites in some quite dense canopy, but once the results are edited to toss out the outliers the typical standard deviations on a collection of 100 points, was less then 50 cm. You can't get that good with a small handheld because they do not have the built in capacity to set technical thresholds for the data types, signal strengths, etc. It all depends upon what the use is for. If you can accept 10 meter accuracy levels a handheld will get you by.

Julian

Reply to post by Julian, on June 21, 2000 at 21:18:17:

Thanks for the follow up. It confirms the understanding I have from working with UMASS and volunteer inventories. If you have 15 or 20 meter lot frontages with 3-5 trees likely across that distance 10m GPS accuracy is about useless and you'll do better with "eyeballed" locations marked on base mapping.

The "street tree" inventory of course gives you many more physical features at known points to relate to than would be found on a development site, particularly a large wooded site. In that instance GPS might be very useful and worth the cost added per unit to data collection cost.

Thanks again.