Currently the extent (dimension) of image-map appearance when displaying svg images as clickable items is dependent on both the image dimensions and device type/orientation.
For example, a wide svg image (e.g. 21:9) has significant white space above and below when being displayed in portrait mode (e.g. phone). The white spaces created unnecessary scrolling for the users.
If we can set the extent manually, even if just the height/width ratio of the extent, we will be able to control how the svg images being displayed, and create a lot more attractive surveys with high quality polygons as clickable items.