We recently got a question from a customer asking how to create GeoPDF maps that have features that turn on or off as you zoom in like the USGS US Topos do. Maps for America! I love it! But I digress. This behavior is something that most Web mapping or GIS types understand intuitively – when you’re zoomed out at a continental view, you don’t see Buford, Wyoming but you do see states and the like. However, when you zoom in, at some point, you see Buford and its Ames Brothers Pyramid. Some features in the US Topos have this scale-dependent property and it’s essential for the usability of those maps. Cartography is not the art and science of putting stuff at the geographically correct position relative to each other on a map – it’s making that geo-contextualized information useful. For the creation of PDF maps, this is where TerraGo Publisher really helps.
ArcMap lets map makers set a range of scales where a layer is visible. Different layers can have different ranges, and of course, the default is always visible regardless of the scale. Publisher lets you choose to propagate that behavior to the GeoPDF maps you create. But it lets you do more. Consider a hierarchy of related features, some you want visible in one range, others you want in another. They’re all the same thing – maybe it’s cities, districts, and neighborhoods, blocks, whatever – but you want different levels of detail depending on the view. Now imagine that pattern repeated a bunch of different times for a bunch of different feature classes. The ArcMap Table of Contents (TOC) is getting messier and messier to the point of becoming useless as a user interface in any generically-exported PDF. Moreover, much, or even most of the information in a map doesn’t need to be on a “layer” at all. With export, you get what you get.
