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Orienting with Holux M-241 + Google Earth Maps (with lat/long grid)
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Gregory Stein
(tauneutrino) - F

Locale: Upper Galilee
Orienting with Holux M-241 + Google Earth Maps (with lat/long grid) on 06/09/2013 07:51:33 MDT Print View


First of all, for orienting I'm using map. Then, compass. I have never used a GPS receiver. But thinking It's maybe a good addition, in heavily treed area/fog/no land details. So let's see, I'll use it 10% of the orienting time maximum. For this reason I want it to be as little and light as possible.

All my gear is using AA batteries; except the camera. Camera is not in my "electronics" category because I'm really serious about photography. It's in a "photography" category with some lenses, filters and small stuff. I've moved from a big and heavy DSLR to Sony Nex-6 mirrorless camera just because of the weight. So now, with 800 gram of photo gear I'm still considering myself UL hiker :)

So I started to look for available options. I don't need GPS receiver with map-on-screen. I need only to know my coordinates. I prefer paper map. Couldn't find AA-powered GPS unit with UTM coordinates. Looked at this Holux M-241 and now I think it might work.

Holux M-241 GPS logger

- No UTM coordinates.

+ Very light at 39 gram w/o battery
+ Powered by 1 AA battery - HUGE+
+ Small
+ Display Lat/Long coordinates
+ No map displayed
+ Could be used for geo-tagging photos (embed GPS location in EXIF)
+ Also it's a neat GPS logger that allows you to show your hike in Google Earth etc etc.

So I have single disadvantage to overcome. After realizing how complicated it is to convert lat/long to UTM I ended up with only option to get lat/long map somehow. In Google Earth if you press CTRL+L you get a lat/long grid displayed. The labels on grid are somehow big, you can change the font size in options (menu). So I thought I can print maps from Google Earth with lat/long grid and use it as reference for Holux M-241.

Will it work in your opinion?
How precise will be this method?
Any ideas?

Sorry for somewhat long post, but I thought it gives the whole picture of the situation.


Edited by tauneutrino on 06/09/2013 07:55:34 MDT.

John S.
(jshann) - F
Re: Orienting with Holux M-241 + Google Earth Maps (with lat/long grid) on 06/09/2013 08:07:19 MDT Print View

Search for "holux"...33 results going back to 2009. I would rather use a garmin foretrex 301.

Dan Durston
(dandydan) - F

Coordinates on 06/09/2013 08:15:09 MDT Print View

That's a nice small size, but no UTM is a bummer. I prefer a Garmin Foretrex or Gecko.

Ken T.
(kthompson) - MLife

Locale: All up in there
Re: Orienting with Holux M-241 + Google Earth Maps (with lat/long grid) on 06/09/2013 08:37:23 MDT Print View

Manfred Kopisch
(Orienteering) - F
Garmin Fenix on 06/09/2013 10:44:11 MDT Print View


have you considered the Garmin Fenix? It is quite expensive, but would allow you to get your UTM coordinates without carrying an extra device. You would get that information from your watch. You would even get basic maps, altimeter, compass, barometer, thermometer, etc. As long as you just look up information from time to time you can go on long trips with the watch. If you turn on tracking you would run down the battery in a weekend, but tracking doesn't seem to be your intent.

Just an idea ...


Edited by Orienteering on 06/10/2013 09:32:54 MDT.

Gregory Stein
(tauneutrino) - F

Locale: Upper Galilee
Hmmm... on 06/10/2013 00:02:12 MDT Print View

First, thank you all for your valuable answers.

I don't see any potential issue if you have a lat/long grid on map and device that gives you location in the same coordinate system. I know, UTM is more intuitive because it has 1km grid. Maybe it's easier to estimate distances on UTM grid. However I can have them both anyway. I can also take a map without lat/long grid and draw it. I think it's 15-20 minutes to do.

I read all the old threads here on BPL before creating this thread. There is maybe one poster here who used it for orienting with map. My concern was about using Google Earth maps since you may have map of virtually any area on the globe. Hence I thought it's worth posting.

Garmin Fenix is far too expensive for me. However that might be a good option.

But still maybe I'm totally wrong ...

Alex H
(abhitt) - MLife

Locale: southern appalachians or desert SW
Re: Hmmm... on 06/10/2013 05:14:49 MDT Print View

Gregory, I am one who has used it just like you describe but with Nat. Geo TOPO printed maps. I would think if the Google Earth maps are accurate (and I assume they are) it would be a fine system.

Hamish McHamish
(El_Canyon) - M

Locale: USA
_ on 06/10/2013 08:17:38 MDT Print View

Gregory, a few observations:

- Does the Holux allow you to change the datum it uses? Google Earth uses WGS-84, but many maps around the world use a different datum, often a local one. If your GPS doesn't allow you to match the datum the map is drawn to, it could cause navigation issues. Often it's not a huge deal, but it can cause major confusion if you don't know it's going on.

- Does the Holux use a high sensitivity GPS chip? Garmins do, and this is what you want when dealing with tree cover or canyon/cliff areas. The Garmins seem to do a good job dealing with the multipath errors common to canyon/cliff terrain.

- Since you only need the GPS to give an occasional point position, a Garmin ForeTrex 301 or 401 would literally provide months of service on 1 set of AAA batteries, especially if you use lithiums. The battery life is so long, and two AAA lithium batts so light, I would just discount the AA/AAA disparity.

If you stick with the Holux, I think you're giving up a lot of capability to maintain battery size consistency.

Gregory Stein
(tauneutrino) - F

Locale: Upper Galilee
OK guys on 06/10/2013 10:47:14 MDT Print View

Thank you for this great input!

I think I'll take both :) I mean I'll buy both. After a good field test I'll sell one of them.

Alex, do you still use it? If you don't, why?

James, you mentioned really important features. Thank you.

- I think that Holux use the same datum (84). I don't think it is possible to change it. However if I'll grid the map I use, then this might be not that important. But it is a lot of work to do, I know.

- I believe Garmin is far better than Holux. It is engineered for my purpose. Holux is a logger and using it for orienting means pushing it's capabilities. I'm pretty sure Garmin will perform better. On Holux website in specs they mention:
Built-in MTK Low power consumption GPS chipset.
32 parallel satellite-searching channels for fast acquisition and reacquisition.
Superior sensitivity, up to -159 dBm.
Built-in WAAS/EGNOS/MSAS Demodulator without any additional hardware.
However I couldn't find such info about Garmin 401/301 for comparison.

- True. Maybe it's impractical, but it would be nice to use same battery in GPS occasionally while hiking, then put it into Zebralight in a camp, then put it into MP3 player and listen to some audio book. This way I consider AA batteries as consumables. I can estimate how many AA/day I consume. Also it will save me 2 ounces (GPS, spares AAA) and make sense for me because power became uniform for all of my electronics.

Thank you!

However again, maybe I'm mad.

Edited by tauneutrino on 06/10/2013 10:49:33 MDT.

Alex H
(abhitt) - MLife

Locale: southern appalachians or desert SW
Re: OK guys on 06/10/2013 15:34:42 MDT Print View

I still use it but only on certain trips. I must state up front that I am a GPS luddite and have always operated with just map and compass until recently. There are a lot of potential draw backs with the Holux like not waterproof and only Lat/Long but many good ones like weight, long battery life, 100,000 waypoints and very low cost. Mostly all I really want is location and some days, distance traveled

I have used it on 3 major desert trips, mostly off trail, 2 of them I recorded track logs which seemed to be very accurate with the exception of a strange track log on one day in some very deep slot canyons but I am not sure it wasn't user error on my part because in other slots it did fine.

The other trip I just turned it on like you are proposing just to check location, also in southern Utah canyon country and it worked perfectly. I was carrying just one Lithium battery for a month long trip and had complete confidence I would have plenty of battery life after having tested it previously on the other trips when I would have it on all day. I have also used it in some deep forest and it also seemed very accurate.

The Gecko is no longer available and the Foretrex's are 2 and 3X more expensive and heavier.

Edited by abhitt on 06/10/2013 16:54:49 MDT.