View Full Version : Large regional map divided into smaller maps?

02-06-2013, 12:13 PM
Already posted this in the Regional/World Mapping forum before noticing this one for help. My apologies for the double post.

Haven't been on the forums here in a while, but I'm starting a new project and I had a question about the best way to start it. Couldn't think of a better place to ask it...

What I'm wanting to do is create a large regional map that contains several nations within it (about 8, I think). I also want smaller maps of the individual nations. Really, I want the smaller maps to be part of the larger one. So I guess the question is: Do I make one large map and then zoom in for the national maps? Or do I make smaller maps for the nations and then try to piece them together? And what pixel dimensions would you recommend (for both scales)?

Does this make sense?

Think of it this way... I'm making a map of Europe, but want the individual countries to also be detailed enough for their own maps. So, do I make a big map of Europe and zoom in to detail Switzerland? Or do I make a map of Switzerland and try to make it fit nicely with the maps of Germany and France and Italy that I've already finished? Maybe that's a little more clear.

Working with Photoshop CS5.5, if that makes a difference.

02-06-2013, 04:28 PM
I'd recommend keeping them separate. A world map and a regional map serve different purposes. On a world map you want to get a quick overview. Then go to the regional map to see a particular country. One map isn't going to do a good job of both tasks.

So I'd start off with the world map, and think what you want to use it for. If you want a poster map, then start with 11 by 17, or 22 by 17 or some other size in that region which will look good on your wall. Set the resolution to 300dpi for good quality print and then get to work in PS. The regional maps are likely to be smaller (unless you want to have a lot of map posters on your walls) and so you can start with a canvas closer to 11 by 8.5 - letter size. That might end up being a little small, but you can always tile a couple of those together.

When creating the smaller maps, make sure you pull in the world map as your base reference. Place it on a background layer and scale it up. If you add the same amount of scaling for each regional map (always blow the world map up to 400% for example), then your sub-maps will end up being pretty consistent and you'll be able to tile hem together (more or less) to create a patchwork world map at the end of the day.

Does that help?

02-06-2013, 04:47 PM
That does help... hadn't thought about scaling it in a background layer. That might be what I go with. And thanks for the tips on size!

02-06-2013, 05:00 PM
No worries! That's the workflow I used for the Midgard maps for Open Design. The world map is crucial for keeping the whole project under control.

02-06-2013, 11:02 PM
Thanks for that little tidbit!!

02-06-2013, 11:05 PM
Ignore this post if your world is flat. Flat worlds are much easier to map.

Done properly, such maps would be in different projections so you can't just "zoom in" to a larger scale. Over a large area (small scale), you are going to have to pick a projection that fits the entire area which will be imperfect and lead to distortion. For a smaller area (large scale), you'll be able to fit the projection to that specific area much better to get a better map. The larger that the larger area is, the worse this becomes.

In terms of workflow, I'd focusing on the geometry of the features in the map, without worrying about presentation. I'd start with a rough idea of the layout at a small scale, then add details at the larger scale, and propagate the improvements back up to the small scale map. Once all that is done, then I'd do presentation. This is approximately how real cartography is done, except in real life we aren't just making up the data but rather have to survey, process, and analyse real world data.

Actually pulling this off without going all out and using real life GIS tools (Which means learning how to use those tools) varies in difficulty depending on exactly what you try to do and how you set up your workflow. Eventually it gets to the point where it's it's worth the time and effort to learn to do it properly with GIS. NASA make a free tool called "G.Projector" which can take maps in a Normal Equidistant Cylindrical projection, and project them to a number of other projections. Normal Equidistant Cylindrical is pretty useless for making a decent looking finished map but easy to convert to other projections. I think one of the other developers around here has a tool that can do transformations the other way without being too complicated but I don't remember who off the top of my head.

If you really want to go all out and try GIS, I've written an introduction to QuantumGIS in the tutorial subforum. http://www.cartographersguild.com/tutorials-how/17469-%5Baward-winner%5D-some-pointers-using-gis.html

02-07-2013, 05:43 PM
I agree with Torstan about using different Maps for the world-view and the regional-view. If you try to put all the regional data in a worldmap it would look totally packed.

But I dont agree with the method suggested to keep the consistency between the different scales. If you scale up a "small" zone of your world map to use it as reference in your regional map you will end redrawing the coastal lines (to avoid the pixelated effect produced by the scale-up of the image). This redrawing would produce shape inconsistencies that could be avoided.

My suggestion is that you should begin your project with enough image size to allow you to use the general shapes of the land masses in your future maps.

Let's talk about numbers. If we are talking about a map of 200x100 centimeters (about 7,1x3,5 inches) the image should have about 21000x10500 pixeles. Create your coastlines with that resolution and then (if you want to work with a small file) resize down the image, BUT allways keeping the original hires file. Then, when you want to create a regional map of a continent or isle open the hires file CROP the area and work on the new file, it will have enought size to give you A4 prints and without doing any resize, redraw o shape modification.