Accuracy of Google Earth Lat. and Long.

 

I have a Garmin StreetPilot i5 and I typically use Google Earth to find new POI's which I then save and load into my unit.

However, recently I have found that the POI coordinates from Google earth are not very accurate. On several occasions, I was several thousand feet away from my destination when the unit indicated I had arrived. In some cases I was in the middle of an interstate with the destination several thousand feet to my right.

Has anyone else encountered such issues? Is it better to enter the POI address directly into the Unit?

My typical process for creating a new POI is:
1. Search for POI in Google Earth using the address
2. Save the location as a *.KML file
3. Using POIEdit, I load and save the *.kml file as a *.csv which I then load using Garmin POI Loader.

Please let me know if the above approach is incorrect.

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TriniInXiSlE

Use Decimal Degrees in Google Earth

On the G-E menu, Go to Tools|Options, and on the 3D View tab, locate the "Show Lat/Long" box, and select "degrees" - so it shows and saves decimal degrees.

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*Keith* MacBook Pro *wifi iPad(2012) w/BadElf GPS & iPhone6 + Navigon*

Accuracy of Google Earth

I usually use Excel when creating POI's in my unit Garmin Nuvi 350 and enter the Lat and Lon and then the place name when using google earth make sure that you have the mercantator feature on and when you find the place there should be a box on the place you are looking for,if you right click on the box click on properties and that will give you the coordinates. What I do is I have both google earth and Excel open so you can copy and paste the coordinates to the Excel fields then save as a .csv file so your unit can read it its usually accurate by a few feet. Hope that helps!

I have also noticed that the

I have also noticed that the lat/long coordinates don't exactly match up between my GPS, Google Earth and several other websites. Although I'm not exactly sure why they don't line up, the fact is that they don't.

I have had very few problems when I just enter the address into the Garmin itself. It always brings me right to the doorstep of where I'm going. The Google Earth coordinates typically put me somewhere in the middle of a nearby park, an interstate, or at least a block or two from my destination. I can always tell when I download a CSV file from the internet somewhere and the author used Google Earth (or similar) to get the lat/long coords.. because it rarely brings me right to the POI. razz

To create CSV files, I usually put the address into the Garmin, save it as a favorite, then connect it to a computer and extract the lat/long coords from the current.gpx file on the unit. Kind of a cumbersome process, I know.. but it's very accurate.

I realize that not all units have this capability, but if yours does, I think it's the way to go. However if you have the Mapsource software, I would assume that you could create your CSV files there with no loss of accuracy, seeing as how it uses the same coords system as the Garmin units.

Anyone know of a website that uses the same coords as Garmins? That would be another good route.

It's all in the format of the coordinates

Make sure you are using the same format in all the applications you're using and they should be within about 10-20 ft on the different maps. For me, the easiest is Decimal Degrees - other formats can be confusing.

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*Keith* MacBook Pro *wifi iPad(2012) w/BadElf GPS & iPhone6 + Navigon*

It's already set on degrees.

It's already set on degrees.

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TriniInXiSlE

DMS vs DD Coordinates

Both coord methods are in degrees - DMS is in Degrees, Minutes, Seconds
DD is in Decimal Degrees - you have to convert from one to the other .
I wrote a little macro in excel that converts DMS to DD !
Not paying attention to format could lead to significant errors !
I just converted Google Earth to automatically give me position in DD format which is required for POI use and accuracy !

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MrKenFL- "Money can't buy you happiness .. But it does bring you a more pleasant form of misery." NUVI 260, Nuvi 1490LMT & Nuvi 2595LMT all with 2014.4 maps !

I have fixed the issue.

I have fixed the issue. Apparently Google Earth put the location in the middle of the interstate. I used the cursor to find the exact long. and lat. coordinates.

Lesson Learned: Double check all coordinates or use the Unit to find the address.

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TriniInXiSlE

Regarding Google Earth

When creating POI's I've learned not to rely solely on Google Earth. I initially start out with GE, but if I have any doubts as to the location's exact coordinates then I'll use MapQuest to compare aerial photos. On more than one occasion I've used my TomTom to verify coordinates.

Mike L.

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Freedom isn't free...thank you veterans! Heard about the tests to detect PANCREATIC CANCER? There aren't any! In Memoriam: #77 NYPD-SCA/Seattle Mike/Joe S./Vinny D./RTC...and God bless Donald Trump!

Use a secondary check on your files

If you are creating a large file, I would recommend running the address data through a second source, such as GPS Visualizer who offers a choice between google and yahoo mapping. Then, you can compare the data and if a few pois differ, you can do further checking.

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Garmin StreetPilot c530, Mapsource

Google Earth

There are many different types of lat/lon datums. Are you comparing apples to apples on your locations???

Thanks for the tip

mkahn wrote:

If you are creating a large file, I would recommend running the address data through a second source, such as GPS Visualizer who offers a choice between google and yahoo mapping. Then, you can compare the data and if a few pois differ, you can do further checking.

I just tried GPS Visualizer, and while it found 2 locations with a negligible difference (Yahoo vs Google), a third location needed further scrutiny as the difference between the two put the location on opposite sides of the street. In that case I guess you can split the difference and put the POI in the middle of the street! smile

Mike L.

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Freedom isn't free...thank you veterans! Heard about the tests to detect PANCREATIC CANCER? There aren't any! In Memoriam: #77 NYPD-SCA/Seattle Mike/Joe S./Vinny D./RTC...and God bless Donald Trump!

Re: Use Decimal Degrees in Google Earth

kch50428 wrote:

On the G-E menu, Go to Tools|Options, and on the 3D View tab, locate the "Show Lat/Long" box, and select "degrees" - so it shows and saves decimal degrees.

I brought up Google Earth and noticed that it has "Degrees, Minutes, Seconds" checked by default. Wouldn't this be more accurate than just Degrees?

Decimal Degree is just as acurate

debroq wrote:

I brought up Google Earth and noticed that it has "Degrees, Minutes, Seconds" checked by default. Wouldn't this be more accurate than just Degrees?

Either format will get you to within the GPSr's margin of error - it's more of an issue of being consistent with which format you are using between your GPSr and the different software applications in use - decide on one, and stick with it. I've found that the decimal-degree is easiest for me to deal with.

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*Keith* MacBook Pro *wifi iPad(2012) w/BadElf GPS & iPhone6 + Navigon*

Decimal degrees required for .csv file

debroq wrote:

I brought up Google Earth and noticed that it has "Degrees, Minutes, Seconds" checked by default. Wouldn't this be more accurate than just Degrees?

The requirement for the .csv file going into a Garmin is decimal degrees. The problem some people have is they take the degrees minutes and enter that as the decimal degrees.
You can use the degrees, minutes, seconds, but you need to go through an additional step of converting (degrees + minutes/60 + seconds/360) into decimal degrees when creating your .csv or .gpx file.

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Garmin StreetPilot c530, Mapsource

Converting Coordinates

mkahn wrote:
debroq wrote:

I brought up Google Earth and noticed that it has "Degrees, Minutes, Seconds" checked by default. Wouldn't this be more accurate than just Degrees?

The requirement for the .csv file going into a Garmin is decimal degrees. The problem some people have is they take the degrees minutes and enter that as the decimal degrees.
You can use the degrees, minutes, seconds, but you need to go through an additional step of converting (degrees + minutes/60 + seconds/360) into decimal degrees when creating your .csv or .gpx file.

Shouldn't your conversion be (degrees+minutes/60+seconds/3600). We don't want to confuse those that are mathematically challenged.
Mike

Yes, thanks for the correction

[quote=Mike107Shouldn't your conversion be (degrees+minutes/60+seconds/3600). We don't want to confuse those that are mathematically challenged.
Mike

Yes, missed the extra 0. Appreciate the vigilance.

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Garmin StreetPilot c530, Mapsource