How to resize maps

[Trenloe]

... but I've read that recommendation before and wondered if it comes from a time when connection speeds on average were considerably slower?

The recommendation I'm referring to is for Unity of 16 million pixels and is recent. This is four times the FG Classic recommendation of 4 million pixels - with a 1MB size recommendation to reduce share time to players. Whereas many users can run images larger than 16 million pixels, the recommendation is there for a few reasons - mostly performance related, but also memory use

[kronovan]

You can use the utility that I linked in post #7 to resize the map so that it will align with any grid size you want.

Well...I've downloaded and installed that application before, but after exploring a bit it gave me the impression it was for placing grids on maps that don't already have them. What I was referring to are maps that already have grids on them, but aren't uniform enough (as in equal ratio for grid unit height and width) for the FGU grid to align with them. I didn't notice any tool in Map Align that lets you remove an existing grid and insert a new one. I know it'll let you create a non-uniform grid by tweaking the height and width controls. I only tried it briefly though, so it's possible I missed something. Or am I misunderstanding the tool's full potential, in that it allows you to export just a grid dimension that you can then import into FGU for that image? If so, how is that even done?

It could be a moot point though, in that the maps I've seen that have non-uniform grids, are so irregular that even the most sophisticated graphics tool probably couldn't do anything to correct them.

[kronovan]

The recommendation I'm referring to is for Unity of 16 million pixels and is recent. This is four times the FG Classic recommendation of 4 million pixels - with a 1MB size recommendation to reduce share time to players. Whereas many users can run images larger than 16 million pixels, the recommendation is there for a few reasons - mostly performance related, but also memory use

16 million pixels fits with what I consider my max size for VTT maps; 11''x17" at 300 pixels. Any of my VTT maps that will be larger than that in print inches, I render at a lower DPI. My 11x17, 300 dpi maps end up being much larger than 4 MB though, even when rendered to JPEGs; usually 10 MB+. That I believe is in part due to the complexity that detailed symbols and polygons add, as well as color info. What mapping tool out there makes a 16 million pixel map that's only 4 MB? I've always read that 1 pixel takes 1 byte of storage at a minimum.

[LordEntrails]

The tool linked by Mr Z and myself is designed for images that have a baked in grid, and that the grid is not always square, regular or grids with an integer number of pixels per square. Yes, if the grid is very irregular, then yes their is little that one can do about it.

For instance, some published maps get tweaked when the layout is done. Such that the image is not scaled proportionally so tat a map might end up with a grid that is 50 pixels horizontally, but 52.221 pixels vertically. The tools can make the image square again, plus is can rescale it so that the grids are a regular number of pixels per square. Such 50 x 50.

[Trenloe]

16 million pixels fits with what I consider my max size for VTT maps; 11''x17" at 300 pixels. Any of my VTT maps that will be larger than that in print inches, I render at a lower DPI. My 11x17, 300 dpi maps end up being much larger than 4 MB though, even when rendered to JPEGs; usually 10 MB+.

There isn't a specific recommendation on image file size for FG Unity - the 1MB I mentioned was the recommendation for FG Classic to keep image share times to an acceptable level in FG Classic. Recommended image guidelines for FG Unity can be found in the Wiki here: https://fantasygroundsunity.atlassia...per+Guidelines

That I believe is in part due to the complexity that detailed symbols and polygons add, as well as color info. What mapping tool out there makes a 16 million pixel map that's only 4 MB? I've always read that 1 pixel takes 1 byte of storage at a minimum.

There are different things that affect image file size - colors per pixel, type of image file compression, image complexity, etc., etc.. 1 pixel could be represented by less than one equivalent byte on average (for example, if Run Length Encoding is used for lossless compression and there are a number of pixels of the same color together) whereas in most instances the maximum is usually 3 bytes per pixel - giving 16 million colors per pixel (although it is possible to go higher than 24-bits per pixel images), but then compression (lossy or lossless) will usually reduce the overall average bytes per pixel.

Most graphical applications will be able to produce a good quality 16 million pixel map at less than 4MB. Here's an example of one of Ryan Wolfe's excellent 0 Hour Armada SciFi ship maps - as you can see, it's actually over 25 millions pixels, but is 2.1MB in file size.

[Zacchaeus]

Well...I've downloaded and installed that application before, but after exploring a bit it gave me the impression it was for placing grids on maps that don't already have them. What I was referring to are maps that already have grids on them, but aren't uniform enough (as in equal ratio for grid unit height and width) for the FGU grid to align with them. I didn't notice any tool in Map Align that lets you remove an existing grid and insert a new one. I know it'll let you create a non-uniform grid by tweaking the height and width controls. I only tried it briefly though, so it's possible I missed something. Or am I misunderstanding the tool's full potential, in that it allows you to export just a grid dimension that you can then import into FGU for that image? If so, how is that even done?

It could be a moot point though, in that the maps I've seen that have non-uniform grids, are so irregular that even the most sophisticated graphics tool probably couldn't do anything to correct them.

The purpose of the tool is to resize a map - which already has a baked in grid on it - so that a Fantasy Grounds grid will align with that grid. I've used it for years on every product I've developed.

It isn't there to remove an existing grid, so yes you have completely misunderstood the purpose of the tool.

The tool was written for Classic which only allowed a square grid so it perhaps has less relevance for Unity now that you can manipulate the grid size to decimal points with different x and y sizes. However it's still a quick and easy way to resize a map if you don't have access to something like Photoshop.

[kronovan]

The purpose of the tool is to resize a map - which already has a baked in grid on it - so that a Fantasy Grounds grid will align with that grid. I've used it for years on every product I've developed.

It isn't there to remove an existing grid, so yes you have completely misunderstood the purpose of the tool.

Yep, in my initial review of it I missed that it will rescale the overall dimensions, either padding or expanding the outer bounds. I can see now where it would be a useful tool to arrive at an even, square grid in a map where it originally isn't.

I find grids most problematic the odd time I convert a a PDF page to JPEG and crop out the map. I find it works about half the time -kudos to the layout folks that manage to do it right- but is irregular for the other 50%. I'm not sure Map Align could have handled those latter maps, but next time I'll give it a try. My tool for mapping is Campaign Cartographer, which always gives me properly dimensioned square or hex grids if I want them. The majority of my campaign maps are custom builds in CC, so I haven't had to resize often.

[kronovan]

There are different things that affect image file size - colors per pixel, type of image file compression, image complexity, etc., etc.. 1 pixel could be represented by less than one equivalent byte on average (for example, if Run Length Encoding is used for lossless compression and there are a number of pixels of the same color together) whereas in most instances the maximum is usually 3 bytes per pixel - giving 16 million colors per pixel (although it is possible to go higher than 24-bits per pixel images), but then compression (lossy or lossless) will usually reduce the overall average bytes per pixel.

Most graphical applications will be able to produce a good quality 16 million pixel map at less than 4MB. Here's an example of one of Ryan Wolfe's excellent 0 Hour Armada SciFi ship maps - as you can see, it's actually over 25 millions pixels, but is 2.1MB in file size.

That's good info, many thanks for posting it. I rarely make maps with a solid color background, but for sure when I have they render much smaller.