Lowrance H2O question

[mojoputter]

H2O users, I have attemtped to enter longitude & latitude numbers on my H2O that I have gotten off of Lakemaster maps, but it does not end up on the lake of the map I have. Is there some kind of a conversion I need to do with those numbers off the maps..?

[PerchJerker]

You need to make sure you're using the exact same coordinate system (ie. exact same format) in your H2O as what is used on the LM map you're using.

[herefish101]

Is there more than one format for coordinates. I thought that was somthing that was the same no matter what, otherwise whats the point, your map could tell you one thing your gps another, so then what do you tell the forest ranger if you have an emergency, if you have one format and they use another. I think your just inputing the numbers wrong or pressing the wrong button, i'm pretty sure there is only one format for coordinates, I could be wrong, If I am wrong, please someone correct me so I to can learn.

[PerchJerker]

There are many formats for coordinates.

The two most popular are degrees minutes seconds --- something like N 47 10 30 ---- or degrees minutes ---- something like N 47 10.500. If you enter the coords from one format into another format, the "wrong" format will give you the wrong position.

[Wish-I-Were-Fishn]

H2O users, I have attemtped to enter longitude & latitude numbers on my H2O that I have gotten off of Lakemaster maps, but it does not end up on the lake of the map I have. Is there some kind of a conversion I need to do with those numbers off the maps..?

It is possible you have them entered correctly, but have a bad map. If it is not a re-surveyed map, it can be way off.

[herefish101]

There are many formats for coordinates.

The two most popular are degrees minutes seconds --- something like N 47 10 30 ---- or degrees minutes ---- something like N 47 10.500. If you enter the coords from one format into another format, the "wrong" format will give you the wrong position.

I guess I need to do some reserch, I just always thought coordinates were standardized, well you learn somthing new every day. Thanks for the lesson PerchJerker. I'll post my findings.

[herefish101]

This is some good info that I found

GPS Conversions and Converters

GPS coordinates can be written in several ways but sometimes the coordinates you are given may not be suitable for your needs. In this guide we shall look at what typical GPS coordinates consist of as well as ways in which you can convert them from one form to another.

Components of typical GPS Coordinates

In its simplest form, GPS coordinates consist of a number of degrees. However, if you are trying to differentiate between North and South latitude or East and West longitude it gets a little more difficult.

Typical GPS coordinates are made up of three main components – degrees, minutes and seconds.

Degrees are the easiest part of the coordinates to work out. The Earth is divided into 360 degrees and this is divided into half with East and West for longitude and North and South as latitude. The maximum ranges for longitude are 180 W (which can be written as -180) and 180 E (written as 180). Latitude has a maximum range of 90 N (written as 90) and 90 S (written as -90).

Minutes are another component of typical GPS coordinates that help the coordinates become more accurate than if they simply contained degrees. Minutes help give an exact point between the degrees – and are divided into 60 seconds.

Seconds can only exist if the coordinate has minutes – but are also optional. Seconds divide minutes into 60 to make a more exact coordinate. To convert seconds into minutes, for example, 41 seconds is equal to 41/60 = 0.683 minutes.

Standard forms of GPS Coordinates

There are three standard forms of GPS coordinates. They all represent the exact same data with the same precision but are simply represented in a different way.

The first form of GPS coordinate is a coordinate containing degrees, minutes and seconds; the next way is just to have a coordinate containing degrees and minutes; or the coordinates can contain only degrees.

If you are provided with a GPS coordinate that you do not want to work with – there are simply ways of converting them that we shall look at below.

Converting GPS Coordinates from DMS (Degrees, Minutes and Seconds) to Decimal Degree

If you have a GPS coordinate that is written in a DMS form – including the degrees, minute and seconds but you would rather have it in a decimal degree form then it is incredibly simple to do the conversion. A decimal degree form of GPS coordinates represents the same information as DMS form but as a decimal and only referring to the latitude and longitude.

If your coordinate is, for example, W92⁰53’51” then you must first calculate the number of seconds. To do this use this sum: 53’51” = (53 x 60 + 51) = 3231.

Next you need to divide the number of seconds by 3600 to give you the fractional part of the decimal degree. 3231/3600 = 0.8975.

You then simply at the whole degrees in the original coordinate to the fractional degrees to get your decimal degree GPS coordinate which should be 92.8975. However, remember that because it is a West coordinate you must negate the result to be ­-92.8975. If it were East then you could leave it positive.

Converting GPS Coordinates from Decimal Degree to DMS

Next we shall look at how you can convert a decimal degree GPS coordinate into a DMS form.

Firstly, to be able to fully convert it you will need to know whether it is a latitudinal or longitudinal coordinate – however you can still partially convert it without this information.

We shall use the coordinate of -84.432 for our example. Firstly, subtract the whole number part of the coordinate to leave 0.432.

Then multiply the fractional part by 60 to give the number of minutes. 0.432 x 60 = 25.92. The 25 is the minute’s portion.

You then take the fractional part of the previous sum and multiply that too by 60 to produce the number of seconds. 0.92 x 60 = 55.2. You can either round the result to 55 seconds or leave it as is.

You should end up with a result of W84⁰25’52”.

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[mojoputter]

Thanks for the info...but now I have a headache after all that thinking

There must be somewhere on my gps that tells me what kind of coordinates its set to use.

[herefish101]

O.k. so I just got off my butt and went and got my H2O, it works on the decimal type of coordinate, so if your map is in the minutes and seconds format all you have to do is use the convertion in my earlier post to make it work in decimal format. If your not trying to keep these coordinates a secret post them and i'll convert them for you.

[jac714]

Make sure you are using the same datum both in the GPS adn on the maps, I knw there are at least two different datum sets and they are not interchangeable. The datum has to do with the survey methods used to make the maps.

[mojoputter]

OK, I figured it out without having to use any conversion. I changed my H2O coordinate system to Degrees/Minutes and punch in the numbers and I'm there...WOOOHOOOO

[herefish101]

Good job, I didd'nt even know you could do that. So from this one thread I learned that there is more that one coordinate format, and you can change which format your H2O uses, SWEET! I love learning new things.