April 13, 2021

Working with Online Data in Global Mapper

Written by: David McKittrick


At the risk of sounding like an ‘old fogey,’ today’s generation doesn’t know how easy they have it. Back in the day, if we had a hankering to binge-watch the Star Wars trilogy (yes kids, back then it was just a trilogy) back-to-back-to-back, we had to trudge down to our local Blockbuster store in the vain hope that someone else had not already snagged the last VHS copies. Inevitably they had, and we had to content ourselves watching Back to the Future… again. Things are different now. Music, movies, TV shows and more can be accessed online and on-demand, and we don’t even need to remember to rewind. Streaming services have fundamentally changed how we are entertained, which, if the truth be told, has been a godsend during our collective state of isolation over the last 12 months. 

Streaming services have also changed how we access geospatial data. The latest imagery, topographic maps, high-resolution terrain, environmental data, climate information, and much more are all now available at the touch of a button. Our GIS projects can be brought to life with detailed basemaps, 3D terrain models, and real-time weather information, all streamed and displayed in conjunction with our personal data layers. 

Global Mapper Dialogue Box

In Global Mapper, accessing these remotely stored datasets is as easy as loading or importing files from your hard drive, and this process is further streamlined due to the fact that dozens of free online data services are built directly into the software. To see what is available, simply click the Online Sources button on Global Mapper’s introductory screen or the globe button in the toolbar. The resulting dialog box displays an organized list of data categories, each of which can be expanded to show the available data services.

Some of the more popular options on this list include:

Topographic Map in Global Mapper


US-based users can stream the latest NAIP imagery hosted by the Dept of Agriculture or high-resolution data from the US Geological Survey National Map program. For worldwide users, the World Imagery offering provides a seamless conglomeration of imagery derived from multiple sources.


Options for streaming raster elevation data include the 10-meter resolution National Elevation Data (NED) and the higher resolution 3D Elevation Program (3DEP) data, both of which are hosted by the USGS. Terran data services with worldwide coverage include the ASTER GDEM and SRTM data.

Topographic Maps

For the US, the entire collection of the USGS topo maps can be streamed. The specific series (1:24,000, 1:250,000, etc.) will vary based on the zoom level of the map display. On-demand topo maps are also available for the rest of the world.

Open Street Map

The product of an ongoing, worldwide collaborative project to create the most complete map of the world, the streamed OSM data provides a highly detailed basemap, which includes roads, points of interest, building footprints, and much more.

Delving a little deeper into the list reveals some more specialized data services, such as climate and atmospheric conditions selectable by date, geologic maps, and navigation charts.

The preconfigured list of data sources can be supplemented with additional online services that are locally available. These might include publicly available data, such as Web Map Services (WMS) hosted by a government agency or academic institution, or private data servers administered internally by a company or organization. In either case, adding these new online services to Global Mapper is a simple, one-time procedure. Click the Add New Source Button, choose the type of service (WMS, WFS, EsriRESTful Service, etc.), and enter the appropriate URL. 

Regional Map in Global MapperBefore connecting to a selected online data service, Global Mapper offers a number of options to determine the extent of the data that will be streamed. If there are no layers currently loaded into the software, the full extent of the online data will be displayed by default. If one or more layers have been previously imported and are displayed on the screen, the default setting is to limit the extent of the online data to the current screen bounds. In either case, these defaults can be overwritten by selecting one of several alternatives, including limiting the streamed data to a specified radius of an address or lat/long, within a defined coordinate boundary, or within the extent of a selected polygon.

It is important to note that while Global Mapper provides direct access to these online datasets, they are not hosted or managed by Blue Marble Geographics and as such, there is no guarantee that they will be available at any given time. Servers may be temporarily taken offline for maintenance, or the usage threshold for a particular data source may have been reached. Furthermore, many Global Mapper users work in the field or in remote locations where reliable internet access is not always available, so real-time streaming may not be an option. For these reasons, it is always a good idea to download the online data for an area of interest so it will also be available when offline. This simply involves exporting the data to a suitable file format and manually loading the file into the software.

Global Mapper’s online data streaming functionality offers numerous benefits.

  • It provides immediate access to a variety of relevant data layers for a project area, regardless of scale or location. 
  • It reduces the local storage requirements when a high-resolution basemap is required for a particular map view.
  • It scales the data automatically so the resolution is optimized for a particular zoom level, which means that a wide geographic extent can be rendered as quickly as a localized large-scale view. 
  • Because the data is maintained remotely and is often periodically updated, the data available in Global Mapper will always be the most current.
  • The list of preconfigured services is being continually revised and is dynamically updated without the need to install a new version of the software. To that end, if you find an online datasource that you would like to have added to the list, send the link to geohelp@bluemarblegeo.com.

Global Mapper’s ability to consume data from such a wide variety of public and private online services is a testament to one of its defining characteristics: its limitless interoperability. Regardless of the data source, whether in one of the 300+ supported file formats, a web map service, or an enterprise database, this remarkable application can work with them all. This ensures that the process of transitioning to Global Mapper from your current GIS platform to take advantage of its myriad capabilities, is as simple and painless as trading your Blockbuster membership card for a Netflix subscription.

If you would like more information about this component of Global Mapper, be sure to sign up for the GeoTalks Express webinar scheduled for April 21st. During this free hour-long presentation, Blue Marble Application Specialists will demonstrate the software’s online data functionality.

If you are new to Global Mapper and would like to explore this and other features and functions of the software, you can download a free evaluation copy. If you have any questions, don’t hesitate to get in touch

If you enjoyed this blog, you may also find these other resources useful:

All About Online Data in Global Mapper

GeoTalks Express: Accessing free online data in Global Mapper

Top 10 Global Mapper Features


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