6 replies to this topic

[Mapper_Mac]

A fellow employee and I have been talking about how to orientate your map before printing. We work in WGS 84 UTM and we have conflicting views on whether or not to tilt the data frame towards magnetic north or keep it how it is projected. I was taught that as long as you reference where magnetic north is on your map there really isn't a reason for tilting your map towards it. Also, when you tilt the map that has a grid on it, the grid lines appear to slant so that they are no longer straight up and down. He disagrees, saying that your map should always be orientated towards magnetic north. Can anyone provide some insight on this?

[patdunlavey]

I'm guessing your friend is an orienteer. Orienteering maps are normally oriented to magnetic north (and do not include other reference grids - a GPS is considered an artificial navigational aid and is not permitted). Of course MN does drift in time, but the high level of detail found on these maps will probably go out of date long before any user with a hand-held compass might notice that magnetic north doesn't seem quite right.

[Mapper_Mac]

Thanks. That's kind of what I thought. Yes, he is all about orienteering.

[frax]

I think it very much depends on how the map will be used.

[Alok Pathak]

A fellow employee and I have been talking about how to orientate your map before printing. We work in WGS 84 UTM and we have conflicting views on whether or not to tilt the data frame towards magnetic north or keep it how it is projected. I was taught that as long as you reference where magnetic north is on your map there really isn't a reason for tilting your map towards it. Also, when you tilt the map that has a grid on it, the grid lines appear to slant so that they are no longer straight up and down. He disagrees, saying that your map should always be orientated towards magnetic north. Can anyone provide some insight on this?

Hi, I saw your question.Please find the an explanation.
WGS 84 is basically a standard spheroid reference system based on the coordinates (X and Y)The center of this coordinate system the center of the earth.These are basically the latitude and longitude on the surface of the earth.It all based on the angular measurements from the center of the earth.The angles on the X-Y plane defines the longitudes and the angles on the Y-Z plane defines the Latitude.
Where as Magnetic poles are all together a different thing.It is based on how the the magnetic forces originating from the center of the earth aligns.The alignment of these forces defines the Noth and South poles of a magnet.It is not fixed.It keeps on changing.( Pleaes check for polar wordering curve on Google)
So what ever you are doing is all based ob the angular measurements and not on magnetic forces.Therefore there is no need to tilt the map towards magnetic north.
Thanks
Alok
alokpathak@infobase.in

[Geographic Techniques]

My experience with creating O-maps (usually modified from int'l standard) is by orienting the map with grid north, or true north, at the top. Magnetic north is then indicated by a series of lines with arrowheads running across the page oriented toward toward MN. Of course, the magentic declination is only applicable at the time of map creation since it is constantly changing.

[GeoMapper]

I would suggest keeping your map oriented to true north but adding the magnetic north arrow and noting the declination.