Help re-sizing map images so its grid matches the FG grid overlay.

[Baron28]

One of the biggest problems we all have with maps is getting the FG grid to lay exactly on the map image grid. Here are the steps to solving this problem:

1. Open your image up in Paint.net. If you don't have this tool, google it and download it.
2. Open up a calculator.
3. Change the cursor in Paint.net from a drawing tool to a selection tool
4. Size the map image so you can clearly see the map image grid.
5. Draw horizontally around 10 squares. On the status bar in the lower left corner, you will see the area of your selection. For example, mine was 72,8
6. Divide the number of pixels selected horizontally (72) by the number of squares on the map selected (10) = 7.2
7. On the status bar in the lower right corner, you will see the image dimensions. My image was 1024,768.
8. Divide the total number of horizontal pixels (1024) by our number from step 6 (i.e. 7.2) = 142.22
9. Multiply the number from step 8 (i.e. 142.22) times 24 = 3,413.33. Why 24? It has a ton of divisible factors, 2,3,4,6,8,12.
10. Click Image in Paint.net to re-size the image. Put a check-mark in the aspect ration Enter 3,413.33 for the horizontal value.
11. Save as jpeg.
12. Add the image to FG images folder in your campaign.
13. Open your campaign in FG and open the image and using the grid tool, trace a 24 pixel square over one of the map's squares.

Now you have a map where its grid lines up with the FG grid you overlay it with.

[Trenloe]

Thanks for posting.

Additional resources around this:

Very similar process shown in Xorn's video here: https://www.fantasygrounds.com/filelibrary/tutorial/xorne-rescale-1a.wmv
Valeros's very handy map alignment utility that does it all for you (no maths involved): https://www.fantasygrounds.com/forums/showthread.php?19813-Map-Align-Utility-to-scale-and-align-map-to-grid

[darrenan]

I highly recommend MapAlign. It's fast and easy to use, and works for almost all digital maps. The only maps you'll have trouble with are those scanned in from hardcopy, which might have some distortion that it can't fix.

[HoloGnome]

Regarding Paint.net comments above and with all due respect to the efforts and videos of others, there is a much easier way to get maps to align to a grid. The simple trick is just to use a large transparent alignment grid overlay.

1. Open Paint.net
2. Open the transparent grid you want to use for alignment (in this case, see attached 50x50 grid)
3. Open the map you want to use (hopefully at at least 300 dpi, so you can resize down without image loss)
4. Create a new layer and copy and paste the grid (say yes to canvas resize)
5. Create another new layer BENEATH the grid layer (since you need to be able to see the grid, of course) and copy and paste the map into it. You now have a known-good 50x50 grid floating on top of your map for alignment.
6. Then just drag and resize h & v of the newly-pasted map image using the drag points (little circles) in the MIDDLE of each side until it aligns perfectly - you will have to adjust each side. Do not drag the corners...and don't worry about scaling each side separately. The grid overlay ensures that the aligned final result will be proportionally scaled and will be perfect.
7. Hide the grid layer (or leave it if your map didn't have a grid and you just wanted to use the overlay to add one), then crop and save - you're done.

No math required - just a simple copy/paste and quick resize op. Whenever you want a new grid, just make one and use it as a transparent alignment layer.

The attached file is 3000x3000 at 72dpi with a grid of 50x50 - should be good enough for most uses. I use Photoshop, but this is the abstraction of my process to Paint.net, since it lacks some of the power and features that Photoshop provides...but will still work great as described above.

Enjoy and Keep It Simple! :D

ps. If someone needs a grid other than 50x50, let me know, and I will be happy to make it for you.

ps #2. If you are adding a grid to an image, then you should proportionally scale it, since there is no predefined grid in the image for alignment and you don't want to screw up the aspect ratio.

UPDATE: I have added transparent grid overlays for 35x35, 75x75 and 100x100.

[Nickademus]

Regarding Paint.net comments above and with all due respect to the efforts and videos of others, there is a much easier way to get maps to align to a grid.

I'm glad to see how to do this in a common program in case I ever need to, but in my opinion the MapAlign utility is just as fast (maybe faster depending on your mouse speed). It's the same idea only in reverse. You open the map, draw a square over the map's grid and click a few buttons to nudge the lines into place over the map's grid. Then you save the file. With maps from the company I normally buy from, I can format a map in around 7 seconds. I usually batch format while I'm playing in a game.

The real problem comes in when the map has squares of different sizes in different areas (due to bad scanning or just being poorly drawn).

[HoloGnome]

Yeah - not dissing MapAlign in the least. :D It's fast and very handy. Just wanted to make sure people knew they could easily use transparent grid overlays of any size in Paint.net. I guess I'll post some others later: 35x35, 75x75, and maybe 100x100. My personal preference is for a paint tool because it allows me to adjust the image appearance, but that's an optional thing.

NOTE: post above now includes the additional transparent grid overlays.

[Andraax]

One of the biggest problems we all have with maps is getting the FG grid to lay exactly on the map image grid.

I don't have this problem. I always use maps without a grid, so the only grid is FG's grid. :-)