Messages

[Does proximity to canyon walls seriously affect the accuracy of GPS units?]

Next newbie question of the day:
Does proximity to canyon walls seriously affect the accuracy of GPS units?


I hiked at a place called Smith Rock near the town of Terrebone, Oregon:
44°22'5.02"N,121°8'21.35"W

It is in a canyon along the Crooked River. The geopoint is at the bottom of the canyon just across a bridge over the river. There is a rock wall face that rises sharply about 800 feet that I walked along at the bottom during the hike. The rock face is vertical much of the way and, as such, is a very popular rock climbing location for serious rock climbers in the Pacific Northwest.

My track for this hike was highly inaccurate which I found surprising. It had me crossing the river numerous times when I did not. It showed me well off the trail when I was not. It was upwards of 100 feet off in some places and was way off when I was right next to the rock wall photographing climbers.

I'm wondering now if the canyon walls were affecting it's accuracy. That would be a disappointment because I will do many canyon hikes.  Some of them with much higher walls adn some including slot canyons.

I know my unit does not have a sirf chipset and that makes a difference. Just how much of a difference I don't really know.

Anyone care to comment on GPS accuracy in canyon settings?

Thank you all for your input. It really helps to clarify things for me.

As I will explain, I think I'll take seldom_sn's suggestion for handling "tracks", which is really treating a "tracking log" segment as a "track". I like that better because it records more data than a standard "track" does and it stores it on the SD card. The ones I will use are the ones titled "Active Log 01" etc. Then I will later rename the log segment to the hike title I want after saving it on computer.

I just need to be sure to upload the active log to computer before it gets recycled in the normal course of events.

If I understand correctly then what I should do to record a hike is make sure I turn off and then turn on my GPS at the beginning of a hike, clear track history and then remember to turn off and turn on my GPS at the end of the hike. That will make sure I create a tracking log segment for my hike. Then later after I upload the logs into Mapsource I will simply go through the log segments individually to identify hikes.

As it stands now, if I save a track under a track name it remains permanent in the unit but for reasons I don't understand is not written as such to the SD card and it strips the date/time stamp, leg time and leg speed.

But I did find I could upload the named tract stored only in the unit and save it off as it's own separate track file that I could export to Google Earth.

Hope I got it figured out now.

[Can someone explain the difference between tracks and the tracking log using Garmin GPSs and help me to create individual hike tracks?]

Newbie question of the day:
Can someone explain the difference between tracks and the tracking log using Garmin GPSs and help me to create individual hike tracks?

Here is my issue...
I want to go to a trailhead, start a track and give it a name and then close the track at the end of the hike. Later I want to map the track of the hike on Google Earth and on topo maps for printing.

My problem: I don't know how.

I think my lack of understanding is related to the fact I don't understand tracks and tracking logs, how to use them and where they are stored. (I'd like to store everything on the SD card)

What I do know:
I can go on a hike and when I return assign a track name using the track function of the unit.

I know that the tracking log is stored at the root directory of the SD card and contains date/time stamped data and that there is one tracking log file automatically created every day. I use that file to Geoencode photographs taken during hikes.

I know that the tracking log does not appear to store the named track because when I open it in MapSource the named track is not listed but a series of logs of unknown nature does appear. I suspect that a new log is created each time the unit is turned on and off, but do not know that for sure.

I know I can see my named track on the GPS unit itself and that I can download it directly from the unit into MapSource through the USB cable and see the named track along with all the other tracks from the unit in Mapsource and that they are all combined.

I know I can convert the tracks to .kml and map them in Google Earth. I haven't tried doing topo map prints yet, but think that would be no problem.

What I can't do:
Separate my named hike from all the other track information

Questions:
Are tracks different from the tracking log? If so, what is the difference? (I think tracks don't hold date/time stamp data but don't know what other differences there might be)

Can you save a named track to the SD card and, if so, how?

How can you separate a particular hike from all the other track information that is collected when the unit is on and store it separately from that for later use?

I don't know how to tell the GPS I am at the start or finish of a hike.

Any clarifications of concepts that help me understand how to extract and save individual hikes would be greatly appreciated.

I don't use this procedure as I log directly to the microSD datacard, but I just tried this with a Vista HCx, MSv6.15.7 under XP pro and it worked perfectly. You two might have some conflicting software causing the problem.

I won't worry and live with it.

Since some folks have the problem and others don't I'll go with it being a MapSource bug related to Vista 64-bit and possibly other OSs. It is not a particularly well done application to begin with so I kinda expect it to be a little rough edged.

edit:fixed quote

I would not be surprised if the Vista 64-bit operating system might be related to the problem.

[Why can't I save a track from MapSource as a .gpx file when I can save it in Garmin's native .gdb format just fine?]

This is probably the beginning of a whole series of newbie GPS questions. My apologies in advance to the group for my ignorance.

Today's first question is:

Why can't I save a track from MapSource as a .gpx file when I can save it in Garmin's native .gdb format just fine?

Is this a known problem with a fix I need to apply?

When I try saving the file in .gpx then MapSource simply unceremoniously quits and displays this message -
"MapSource has stopped working"

The application does create an empty .gpx file before it croaks. Of course all work to that point is lost.

I can convert the .gdb that I can create for use in Google Earth and such but I'd prefer to avoid that unnecessary additional conversion step if possible.

Configuration:
eTrex Vista HCx unit, MapSource 6.15.7 (I believe that is current), Windows Vista 64-bit operating system.

Procedure:
1-Upload tracks from GPS unit into MapSource using USB cable connection with "receive from device..." under the transfer menu
2-Select named track in tracks tab
3-Select "Save as..." under File menu
4-Name file and select .gpx from the pop-up file type list in the save dialog box
6-Click "save"

That is where it dies.

[quote ]
Here's the thing, you can NOT have the unit display waypoints that are loaded to the microSD datacard with the Vista HCx. Load them to the unit's internal waypoint memory and then they will display on the unit.
[/quote]

Bingo! That was my problem. I figured it out on my own but it is nice to get re-enforced that I'm now doing the right thing.

The other thing I discovered is that in my unit, eTrex Vista HCx, the amount of waypoint description information that it loads into the unit is limited to just about 30 characters. I was hoping I could upload all the descriptions I had entered on Google Earth.

I did verify that all the descriptive data was downloaded in the .kmz and .kml files and that when converted to .gpx and .gdb files the all the information was still there. It is when it gets uploaded into the unit that it gets lost.

And it does not matter whether I upload my Google Earth points as Waypoints or POIs. it still get truncated.

Oh well... I guess you can't have everything. LOL!!!

I remember reading somewhere about needing to zoom in closer than 800 feet before they would show up to. I zoomed in closer than that and they still did not show up.

I'm a GPS newbie and just took delivery of a eTrex Vista HCx unit yesterday.

My problem... I can't view pre-loaded waypoints in the unit. I can see them in Mapsource just fine, but cannot in the unit itself.

I can make my waypoints into POIs with Garmin's POI Loader program and see them as custom POIs. That works fine, but I cannot see them as waypoints in the unit at all even though I successfully loaded them onto the SD card as waypoints with MapSource. They loaded as userdata.gpx onto the SD card from MapSource.

Can anyone tell me how to load and display waypoints as waypoints in my Garmin GPS from an outside source?

Background:
Thanks largely to this site I was able to download Garmin's MapSource software, download all the topo maps I need and load them onto an 8GB SD card that I pre-purchased before the unit arrived.

All that works perfect. I put the SD card into the unit and all the topos show up A-OK.

I also loaded my waypoints onto the card in the same send but they do not show up.

My waypoints originate from thumbtack markers on Google Earth. I have about 250 points I want to pre-load into the unit.

To prepare the waypoints I selected and extracted them from Google Earth as a .kml file. Then I used GPSBabel to convert the .kml file into two separate files... one is a .gdb Garmin database file and the other a GPS Exchange .gpx file.

I read the .gdx file into MapSource and all the waypoints show up under the waypoint tab. I did a normal send to device. In my case that was directly to the SD card plugged into my computer workstation, not through the USB cable connected directly into the unit. (That takes WAYYYYY to long)

I checked and the waypoint data file was on the card. But when I plug the card into the unit I can find no way to make the waypoints display. That is what I need help with.

Then I downloaded POI Loader and loaded the waypoints as points-of-interest onto the card. Those I can find and use as "Custom" POIs. Its nice and even the description data is included so I can use it.

Is conversion to custom POIs the way I will always have to get waypoint data from the outside into my GPS unit??