gps 315 confusion

[Guest perthcatt]

complete newbie to the world of gps here. i just picked up a mag 315 based on my reading here and elsewhere. now, i may just be a complete moron, but the manual that came with the unit seems... incomplete. can someone point me to some better documentation or something similar? ive spent a bunch of time on google.com and i simply cant find anything regarding this unit that makes sense.

 

FWIW, my problem right now is this: after i initialize the unit (at my workplace, outside and on a clear day), my location is shown to be n39 00.000 w105 00.000. whatever, i say. later, i set a landmark in front of my house. according to the gps, im over 100 miles from work, while according to my cars trip odometer, im 21 miles away. i must be doing something wrong.

 

sorry for the long post.

 

~james

[Guest navdog]

I havent reinitialized my unit , so I dont remember all the prompts. But you might want to check to make sure you are set to the right map datum.

[Guest ClayJar]

Okay, here's what I believe happened: You initialized the unit correctly, but it didn't have a good fix at work. It takes time for first fix (and it also has to download the "alamanac", which is the current data on which satellites are in which orbits and with which IDs, etc).

 

The coordinates N39 00.000, W105 00.000 are a "confluence" (a place where integer degrees meet), and there is a neat thing called the Degree Confluence Project that's collecting pictures and reports of all the confluences. So, if you look at the N39,W105 confluence, you can see that it isn't exactly where you were (or if it is, I want your job ).

 

Anyway, the GPS receiver thought that you started out at that confluence, which would obviously make it a longer trip home. If you go back to work and mark a new waypoint (with good sky and such), you'll be able to find out where you really are. (You have no problem to worry about, but if you ever need to reinitialize the unit, give it a good 15 minutes of open sky to get fully loaded with all the data it needs.)

 

(Oh, and if you think that post was long, you should see some of mine. )

[Guest perthcatt]

i only *wish* that was where i worked. now i want to actually find that location so i can take a look. thanks both for your suggestions, my map datum is set to the unit default, wgs84, which from what im reading, should be right. im going to step outside right now and try again, this time with patience.

 

~james

[Guest perthcatt]

looks like that did it. i let it sit outside after a reinit for ~10 minutes and it seems to be much better now. 18 miles from my house (as the crow flies, i guess).

 

the thing i dont understand is why the need to give it time to initialize isnt in the manual. oh, well.

 

thanks again!

~james

 

[This message has been edited by perthcatt (edited 17 October 2001).]

[Guest c_oflynn]

Hi,

 

I've got a magellan 315 too. There is some stuff that isn't in the manual. Another neat feature is

1. Goto the map screen

2. Select menu, select pan & scan

3. move the cursor around, now if you hit "mark" it will create a landmark at the location of the cursor, not at the location of the unit.

 

I didn't see that in the manual, but mabey its there You might want to update the unit firmware before you go geocaching too. Go to the magellan website, its there under "Support". however you will need to buy or make a cable (www.geocities.com/c_oflynn and click on "articles" for making a cable)

 

Good Luck!

 

-Colin

[Guest Aquamander]

Clay's right. When you first initialize the unit, it will be on the status page while it aquires the position data. Once this cycle has been completed, the unit will switch over to the position page. Then it will know where it is and you will get an accurate reading once you start moving.

 

You may want to get the 315 user's video. I find it's a good reference for things that may be a bit vague in the manual.

 

The thing I'm curious about is, can the datum be set to the third decimal place in seconds. Mine is only to the second decimal place. (or does anyone know if that even matters?)

[Guest perthcatt]

aquamander...

 

im running fw ver 3.07 on my 315. i can view to the 3rd decimal place, so maybe firmware is the problem. in my extraordinarily limited experience, i seem to understand that only 2 decimal places is a bit less accurate and wont get you quite as close to your goal as you might like. i might be wrong tho.

 

~james

 

ps. thanks c_oflynn forthe tip!