I have a requirement to create a map (or multiple maps) showing four different locations with a bearing compass drawn around each one, oriented towards Grid North.
I was told that each of the original four points will need to have a circle centred on it, with ticks representing 360 degrees. 0 degrees will be pointing to Grid North. The idea is that if one of these locations was in Toronto, Canada (let's say) the student could take a string with one end on Toronto, have the other end of the string on London, England, and be able to tell you that it's something like "The direction from Toronto to London is 19 degrees from North" (this is an example, I don't know if this is true or not).
I'm confused about how to do this on paper, but perhaps I'm just over-thinking things.
Can I use the Vertical-Perspective projection? Gnomonic is highly distorted a large distances which is what this map will have to show. I read that Vertical-Perspective is similar to Gnomonic, and that Gnomonic preserves true direction, but haven't come across anything saying that Vertical-Perspective preserves true direction.
Is there a tool in ArcGIS that I can use to generate the compass? I've drawn them manually, but if there was a tool to generate it, I would be high appreciative.
Best Answer
Any azimuthal projection will do this, assuming you are after Great Circle paths. equidistant azimuthal is probably the best choice for this as it will give you both a bearing and a distance. Like the bearing, distance will only be true when measured through the projection centre. Vertical perspective will work as it is azimuthal, but you won't get the distance, and won't be able to fit the entire globe.
So, if you did an equidistant azimuthal projection with its projection centre in Toronto, then bearings and distances measured from Toronto would be true.