For scaling, I prefer non-visual scale for scenarios like this.

First measure the size of a hex in the image using Info-distance. Try to find points to make this as precise as possible. This is the source size. For my example here, let us assume this is 0.8

Now, measure the the distance on the CC3+ hex grid. Make sure to measure it in the same way, for example between two corners of the hexes. This is the destination size. For my example here, let us assume this is 1.93

Now, just right click :CC2SCALE:, select non-visual scale, set the origin point to somewhere. When the command line asks for the scale, simply type in source size/destination size, i.e 0.8/1.93 straight on the command line, no need to manually calculate it, and then hit enter.

You can move it with non-visual move much the same way. Just figure out how much it needs to move, and then give the distance as @distx,disty. The @-sign here refers to relative cooridnates instead of absolute ones. (Although in this case, perhaps it might be eaasier to just move them to an absolute position)

Hit Tab (while moving something). That changes how cursor previews are rendered.

And it is now in the atlas

The city is now in the atlas

Here's a fixed version.

As Sue also noticed, the line for your polygon was double, so your actual polygon ended up being that o-width space between the "inner" and "outer" lines.

I split it open, then ran DELDUPS to get rid of duplicate nodes, then joined it again.

I might do that one day. It is actually non-trivial to pick a good atlas city for this challenge. If the city is too large, the navigation links gets almost invisible, and if the city is too detailed, it isn't as fun as a contest because the look of the buildings is locked down already, providing little freedom. Some cities also have a very heavy .fcw file which may not be too kind to those with a weaker computer, so I want to avoid using those for a challenge like this as well.

I do have a few other candidates though. But I also try to vary the content of the challenges, so it won't be streets next time.

Nothing you necessarily need, but depending on the detail level you wish to achieve, you could add things like vegetation (bushes/flower/vegetable garden), wagon tracks and wagons, worn trail from the road to the doors, various items (creates, benches, lights, tools), fences, animals, ....

There is, but you'll need to do some trimming.

Basically, you just use clipboard copy and use a selection rectangle to mark the area you wish to copy, then paste it into the destination map (Keep an eye on the command line while doing clipboard copy to make sure you complete all steps).

You can the use tools like :CC2TRIM: and similar to crop lines going out of the area.

Basically, your procedure is the same as when making a detail map of an area, which is described in this blog article, just a bit simpler.

Well, according to the description, they are .png images, so those should be fully importable as symbols.

They are isometric though, so they won't work alongside other DD3 stuff, they'll basically be their own style.

You can use :CC2EDIT: on it.

Note that it can be a bit difficult to target the edge of the red x image, the actual edge seems to be a bit inside the visual edge, into the gray area. (Note that you can "spam-click" this command. Since left button repeats the command, and the command ends whenever you click with a non-valid selection, just keep clicking will reactive the command for another try)