Diagonal lines (Rhumb/Nav Lines)

[Plutonium Blonde]

What Photoshop technique do you use to draw your nav lines?.

For this map I just made two lines that crossed at right angles then copied that layer and rotated it 11.5 degrees and then did that six more times.

Edit: oops, yeah that should be 11.25 degrees.

[Blacky]

I knew it was something so simple my brain would be ashamed to hear of it...

Thanks!

[ravells]

I have what's I'm sure is a pretty dumb question. But hey, we're here to learn.

What Photoshop technique do you use to draw your nav lines? I'm thinking about this for some time now, and for the life of me, I can't find a nice tool to say to PS: draw n infinite lines from this point each with the same angle...

The easiest way is to do it in something like inkscape (or illustrator if you have it) and import it into PS.

If you want to do it in PS, then try this:
Make a new layer.
Select the pencil or a hard round brush of the appropriate size. Hold down the shift key to draw a horizontal or vertical line.
Duplicate the layer 3 times.
On the first duplicate layer Ctrl-T to activate the transform tool.
Hover the mouse just to one side of a corner bounding box until it turns into a curved double headed arrow (rotate).
Hold down the shift key (to constrain rotation to 45 degree increments) and rotate the line by 45 degrees. Hit enter to accept the transformation.
Do the same again with all the other duplicate layers.
If you have fingers like an octopus, instead of duplicating the layers you can press Ctrl-Shift-Alt-T which will make a new line on a new layer for you to rotate.

[Midgardsormr]

You could get some nice tapering lines using the Shape Tool. Set it to polygon mode, 16 sides, and in the option drop-down (a down arrow at the right end of the list of modes in CS4), tick "Star" and set the indent to 98%. Hold down shift while drawing your star to constrain the angle.

edit: Oh, and I think you'd want 11.25 degrees, not 11.5 for that earlier tactic.

[Hai-Etlik]

I don't know if you would find this easier or not, but I wrote a program for generating Rhumb lines: http://www.cartographersguild.com/sh...Line-Generator

It produces SVG images as output so you can scale and work with them in a vector program like Inkscape and then export to a raster if you want.

[sambrookjm]

Huh...I'd written this script for a completely different purpose, but it fits here as well as anything else. This GIMP script (JMS-Rhumb.zip) can draw any number of Rhumb Lines from 3 to 360, from nearly any point on the map (10%-90% in the X and Y directions) The map can be just about any size. Unzip it, and put it in your GIMP script files folder. It will appear in the Filters-->SambrookJM menu...feel free to change that to wherever you would like. I've also attached a sample gif of what it looks like with 32 lines.

Getting rid of all of the commented code will connect each of the lines to the ones next to them to get a nice curved surface.