Consistent Map Scaling with Wonderdraft

[Aizenvolt]

I made an 8000x8000 map with wonderdraft. I wanted it to have earth circumference(earth has 40,000km circumference so each pixel on my map represents 5km). My linear scale has 2000 width, 10 segments and 1000 segment distance. The resulting linear scale goes up to 10,000. Now I want to take a continent of that map that is around 18,000 km(width) and make a more detailed map for it with create a detailed map option from the menu. What I don't understand is how to create a consistent scale for that new zoomed map.

[Redrobes]

Are you asking how big does the bitmap and scale need to be for the new 18,000km continent ? Or is this more about how do you do it in Wondercraft via the menus it has ?

It would seem to me that if you make a map that just fit this continent on it and it too was 8000 pixels wide then each pixel is 2.25km wide and that a 2000 pixel scale will be 4500km.

Bear in mind all of these scales and measurements are valid only for the equator. If you have a globe then it depends on what kind of projection your using as to how that maps to the pixel scale at any point. For example, with a usual Mercator projection then the distance at the poles is very small so now you have "very small" / 8000 km/pixel values.

It is also more normal to have a 2:1 ratio map for globes with a Mercator projection since there is +90 at the north pole and -90 at the south pole. But full west is -180 and full east is +180 in degrees. So you have 360 left/right to 180 up/down or 2:1 for equal angles/pixel of longitude and latitude.

[Aizenvolt]

Are you asking how big does the bitmap and scale need to be for the new 18,000km continent ? Or is this more about how do you do it in Wondercraft via the menus it has ?

It would seem to me that if you make a map that just fit this continent on it and it too was 8000 pixels wide then each pixel is 2.25km wide and that a 2000 pixel scale will be 4500km.

Bear in mind all of these scales and measurements are valid only for the equator. If you have a globe then it depends on what kind of projection your using as to how that maps to the pixel scale at any point. For example, with a usual Mercator projection then the distance at the poles is very small so now you have "very small" / 8000 km/pixel values.

It is also more normal to have a 2:1 ratio map for globes with a Mercator projection since there is +90 at the north pole and -90 at the south pole. But full west is -180 and full east is +180 in degrees. So you have 360 left/right to 180 up/down or 2:1 for equal angles/pixel of longitude and latitude.

I use wonderdraft. Can you tell me what is the formula I can use to calculate what the selected map area's distances will be depending on the zoom ratio I chose? For example I have an 8000x8000pixel map and I choose a 4000pixel width area and I zoom with 2x ratio so the chose area will be presented in 8000x8000pixel (I chose the are with create a detailed map option from wonderdraft menu).How can I calculate the size of each pixel in the new map(in the original 1pixel=5km). Also how do create a new consistent graphic scale for the new zoomed map?

[Redrobes]

If you start with am 8000 pixel image which has each pixel being 5km then if you zoom in 2x and expand the region back to 8000 pixels then each pixel will now be 2.5km.

So pixel distance = 5km * new_image_pixel_width / original_map_pixel_width * region_pixel_on_original_map_width / original_map_pixel_width.
I.e. 5km * 8000 / 8000 * 4000 / 8000 = 2.5km

It might be easier to work in distances instead of pixels. So originally for your 8000 pixel image it was 40,000km. If you take half of the image you have 20,000km. Now you can pick a convenient scale like 1 pixel = 2km and have your map 20,000 / 2 = 10,000 pixels wide.

Or you could keep it 8000 pixels wide and know that your scale is 2.5km per pixel. Keep the scale the same length of 2000 pixels but instead of cutting it into 10 x 200 pixel bars of 1000km each, you cut it into 5 x 400 pixel bars of 1000km or 10 x 200 pixel bars of 500km.

(all of these numbers are at equator only of course)

Oh and I have not used Wondercraft so I don't know the menu options to use to make this happen but I am sure its fairly easy to set up.

[Aizenvolt]

(all of these numbers are at equator only of course)

For an equator I just need to make the width double the height right? Meaning 8000x4000 pixel? Also does this mean that the areas that I choose to zoom must also have 2:1 for the linear scale to be accurate?