By Charlie Frye, Esri Chief Cartographer
The Mapping Center Team is pleased to share the ArcGIS Online News announcement that includes the availability of the new World Topographic Map. As several members of the Mapping Center team played a significant role in the design and production of this map, we would like to begin telling you about this map. The World Topographic Map covers the globe to about 1:1,000,000 scale. Within the U.S. (excluding Alaska), the map scale extends to about 1:18,000. The map is a cached map and uses the Virtual Earth/Google Maps tiling scheme (WKID = 102113). What follows are some of the essentials everyone should know about this map, including that the service is free.
As with any map, we start with the audience — you — the ArcGIS user who needs a topographic base map and doesn’t have the time, data, or training to make one. The purpose of the map is to provide a base to underlay and geographically contextualize your GIS data content.
The map is designed to be mashed up on. We purposefully omitted the darkest and brightest colors from the map so you could use those colors to symbolize the data you will be overlaying on this map. As a result, the “unadorned” view of this map looks a little washed out. Here are a couple of examples: flood plains in Sioux City, IA and hydrologic units with NWIS and STORET gauging stations. (Click on the images to see the full size versions.)
The World Topographic Map was created using best available data. We will improve this map over time as we learn of and acquire better data. More candidly, this map is, and will be a community-wide effort, with Esri facilitating the compilation of uniform cartography. We want to work with any of you who have better data, and we’ll cover more about how that will work in upcoming blog entries.
Like most online maps, the quality of the map can be largely attributed to the community of data providers. In particular, the U.S. Geological Survey’s EROS Data Center provided terrain and land cover data, and the U.S. Environmental Protection Agency, with assistance from the U.S. Geological Survey, provided NHDPlus hydrography data. Without these data sets, the World Topographic Map would not have been possible and thus, we are greatly indebted to these organizations. There were many other organizations that also produced data we used, and the REST endpoint of the map service gives credit at the service level and at each map scale. We are also in the process of compiling a more accessible list of data sources.
The new Esri Map Templates Resource Center is where you can find and download map templates that show how to make your own local edition of the World Topographic Map. We actually tried this out ourselves and produced detailed maps at scales down to 1:1,000 for Portland, OR and Philadelphia, PA. For these maps, we owe thanks to Metro (Portland Metropolitan Area) and the City of Philadelphia and PA GIS Data.
If you use the Virtual Earth Example and have not yet downloaded the Bing Maps 3D (beta), here is an example of what this map looks like in 3D (Click to see full size view of Mount St. Helens):
There’s a lot more that could be said about the World Topographic Map and its related map resources, but first we simply wanted to alert you to its release. We’ll be writing more about specifically how we symbolized, labeled, and compiled this map in future blog entries.You can also visit the ArcGIS online hopepage for the World Topographic Map.