This guide shows how to add and modify physical size info in 3D maps.
Physical size works by setting a DPI value, which, together with the map's pixel width and height, is able to store real world physical size.
DPI means Dots Per Inch - the dots in our case are pixels, so it actually means pixels per inch. For example, suppose you have a map with 1024 x 1024 pixels: if we set this map to a DPI of 1024, it will measure one inch of real world physical size. By setting DPI info, we're saying those 1024 pixels will fit in the space of one inch (or 2.54 centimeters). In this way, we can store real world size information in our maps.
Since physical size depends on DPI information, it only works with image file formats that can store it: PNG, TIFF, JPEG, BMP formats.
You'll see sizes displayed in centimeters (cm) or inches ("). This can be changed in the Preferences window.
Let's see how it works by creating and editing a map's physical size information. Before starting, please make sure you can see the entire text of this guide window without scrolling - resize it if needed.
Start by clicking the New Map button at the top of the Editor.
Suppose our map's size in pixels will be 4096 by 4096. Please enter these values in the Size Width and Height fields.
Next, if disabled, enable the Physical Size Info switch below.
The DPI field shows the Dots Per Inch value: how many dots (another name for pixels) fit in one inch (or 2.54 centimeters). This relation between pixels and a physical size is what we need to set physical size information on our maps.
Try changing the DPI value and look at the Width and Height values that appear below. With the DPI field focused, you can simply move the mouse wheel up or down to change values.
By changing the DPI value and/or the pixel Width and Height above, you can define the physical size info of the map.
Click the Create button to create a new map with the given physical size info.
Check the area right below the Editor, on its left side: you'll find the physical size info that your previously chose, next to the pixel size.
If pixel width and height sizes are equal, you'll only see one value, like "30.0 cm", which is the side size. But if the map has different pixel width and height sizes, two values will be listed.
In the same manner, when you open a file in formats that store DPI information (PNG, TIFF, JPEG, BMP), you'll also find its physical size info listed in this area.
You can change the physical size info in the Transform tool, at the bottom of the Map Tools area.
The controls are exactly the same as we've seen in the New Map window, they are located in the Final Size area. Set the DPI field to an appropriate value, but if possible, avoid changing the pixel sizes, as it will resample the image.
Using this tool you can apply or correct physical size information/DPI values in any maps, including those created in third party apps.