Horizontal and Vertical Hex Grids Misnamed?

When I go in to the settings of a map and select vertical hex grid, roll20 gives me a horizontal hex grid, and vice versa. Roll20 uses the exact opposite of the terminology that I have seen used everywhere else, e.g. Hexagonal Grids : The typical orientations for hex grids are vertical columns (flat topped) and horizontal rows (pointy topped). Does anyone know why roll20 labels them backwards? Followup question, what logic does roll20 use to calculate the width and height of a hex grid?  If I set the dimensions to 3x4, I get this: Which is neither three hexes wide nor four high.  Similarly 4x3 gives me:

If Roll20 were to decide to change the terminology, a good choice might be to switch to "rows" (flats on the sides) and "columns" (flats on top and bottom), to avoid invalidating any previous references and the confusion that would ensue.

keithcurtis said: If Roll20 were to decide to change the terminology, a good choice might be to switch to "rows" (flats on the sides) and "columns" (flats on top and bottom), to avoid invalidating any previous references and the confusion that would ensue. Well, the meanings of the terms "vertical hex grid" and "horizontal hex grid" are very well established, as the opposite of how roll20 uses them.

The hex grid is very.... superficial.  It is more like some sort of mathematically calculated overlay over the top of a square grid.  When I create a map page that will be hex, I set it up on the square grid, and then change it to hex as my last step.  Any dimensions you are trying to set up on the map page are still utilizing the underlying square grid, and that is why your 3x3 isn't working. I'm assuming that hex grids must be horrible to program for, since I haven't tried a vtt that does a good job with them so far.

True. But in the absence of the ability to go back and reverse every instance where they have been used in the past, I was suggesting another, also common terminology. This is the terminology used by Worldographer (Hexographer) for example.

Kraynic said: The hex grid is very.... superficial.  It is more like some sort of mathematically calculated overlay over the top of a square grid. Ah, right, now I get it. Outside of roll20 I created a 3x4 grid of blue squares with sides 70 px (the roll20 default).  Then I overlaid on top of that a green grid of vertical hexes using the roll20 default of 81 pixels from edge to edge - that results in the left vertices of the hexes lining up with the vertical lines in the square grid. In roll20 I created a red 3x4 grid, then changed it from squares to "horizontal" (i.e. vertical) hexes.  I uploaded my image to the map layer and this is what I see: So that must be how roll20 does it.  This is good for me to know because now when I create my hex maps externally, I will know what dimensions roll20 thinks they are.  Many thanks for your help Kraynic!