Articles

Regional map of the terrestrial ecosystems of the contiguous United States. Source: NatureServe, 2025.

High Resolution Ecosystem Map of the Contiguous United States and Adjacent Areas

Caitlin Dempsey

NatureServe has developed an updated 30-meter hexagon map of regional ecosystems in the contiguous United States and adjacent areas.

An oblique photo from the International Space Station of Lake Chapala in Mexico.

Lake Chapala: a Tectonic Lake at Mexico’s Triple-graben Intersection

Caitlin Dempsey

Lake Chapala was formed at the intersection of three grabens.

Annotated satellite image of the Wayombo River.

Rivers that Flow Backwards

Caitlin Dempsey

Read about how the Amazon once flowed east to west and how the strength of Hurricane Isaac once change the course of the Mississippi river.

Map of the location of Point Barrow.

Northernmost Point in the United States

Caitlin Dempsey

Above the Arctic Circle, Point Barrow is the northernmost point in the United States.

Mapping Migration to Twin Falls From Other U.S. Citie, 2016-2020. Data: U.S. Census Bureau, Natural Earth. Map: Caitlin Dempsey.

How to Create a Radial Flow Map Using QGIS

Caitlin Dempsey

Learn how to create a radial flow map in QGIS to visualize migration using metro-to-metro data from the U.S. Census Bureau.

Bar chart show voting versus non voting cardinals.

Map and Chart of Cardinals and the 2025 Papal Conclave

Caitlin Dempsey

The 2025 papal conclave is underway. Here's which countries the 135 voting cardinals eligible to elect the next pope come from.

Shaded relief map with shades of blue showing the location of an iceberg off the coast of an Antarctic island.

World’s Biggest Iceberg

Caitlin Dempsey

The largest iceberg in the world is A-23A, with an area of about 1,240 square miles.

A shaded relief map highlighting Alaska and the lower 48 states with the surrounding countries muted with a semitransparent white overlay.

Only State… Geography Facts

Caitlin Dempsey

Here are some interesting geography facts that are unique to individual U.S. states and do not occur in any other state.

A satellite imager of an anvil cloud formation over the ocean.

Satellite Imagery of Clouds

Caitlin Dempsey

Listed here are different clouds formations as seen on satellite imagery.

A view of a wetland with marshes on either side of a body of water.

Water on Earth

Caitlin Dempsey

Earth holds trillions of tons of water, mostly in oceans. Only 2.5% is freshwater, primarily found in glaciers, groundwater, lakes, and rivers.

Dominant institutions in the field in North America include well-known programs at the University of California Santa Barbara, Ohio State University, University at Buffalo, and the University of Wisconsin–Madison. Figure: GIS faculty working in North American institutions based on whether they earned their doctoral degrees in North America or in other regions, Kang & Chen, 2025.

Where are GIS Professors Hired From?

Caitlin Dempsey

Researchers analyzed GIS faculty hiring data to identify geographic patterns influencing job placement.

A collage of satellite images showing various agricultural patterns.

Types of Agricultural Patterns Visible from Space

Elizabeth Borneman

Agricultural landscapes, when viewed from space, reveal distinct patterns shaped by historical practices, local geography, and technological influences.

Two world maps shaded in green for 10% and 30% forest area.

Defining How Much of the World is Covered by Forests

Caitlin Dempsey

With no universal definition, mapping and comparing forest coverage around the world is challenging.

A satellite image of a peninsula with a turquoise lake.

Glacial Flour Makes Some Lakes Turquoise

Caitlin Dempsey

Glacial flour, the fine dust created as glaciers move over land, turns lakes a turquoise color by reflecting blue and green light.

Geography Printables

Caitlin Dempsey

GeographyFun features maps, crosswords, and word searches for educators, students, and geography enthusiasts who love exploring the world through words.

A massive plume of sand and dust was pushed northward from the Sahara desert by the calima, a warm southeasterly wind prevalent in North Africa in the winter, as seen in a satellite view of Spain and Portugal. Image: February 21, 2016, NASA.

Deep Space Mapping of Saharan Dust Height

Caitlin Dempsey

Researchers used four years of measurements from a deep space satellite to calculate the average monthly heights of Saharan dust clouds.

Map showing the NDVI anomaly in 2024 compared to average levels from 1991 to 2020). After a couple of years of above average precipitation in Southern California, vegetations levels in the summer of 2024 were 30% greener than average. Map: NASA, public domain.

Hydroclimate Whiplash: the Impact on California Wildfires

Caitlin Dempsey

Hydroclimate whiplash - the rapid swing between drought and heavy precipitation - plays a role in the increasing intensity of California wildfires.

A photo taken from space that has been labeled with place names of an open water estuary.

Florida’s Largest Open Water Estuary

Caitlin Dempsey

Covering an area of about 400 square miles, Tampa Bay is Florida's largest open water estuary.

A Tweet from 2020 comparing a map to an animal.

Cartopareidolia: Seeing People and Animals in Maps

Caitlin Dempsey

Cartopareidolia is the phenomenon of seeing people and animals in maps.

A screenshot of an application showing a basemap of the SF bay area with blue lifework on top of it.

Shapefile Viewers

Caitlin Dempsey

Explore viewers for visualizing GIS vector data in shapefile format, available for both desktop and web browsers.

Sado Island: An Example of Tripartite Geography

Caitlin Dempsey

Sado Island is an example of a landmass with tripartite physical geography.

Visualization by NASA showing the retreat of the Smith Glacier grounding line between 1996 and 2011.

Understanding Glacier Grounding Lines

Caitlin Dempsey

Grounding lines are the boundaries where glaciers and ice sheets transition from resting on solid ground to floating on seawater.

With pansharpening, the panchromatic Landsat spectral band can be used to increase the resolution of Landsat imagery.

Pan Sharpen Landsat Imagery in QGIS

Caitlin Dempsey

This QGIS tutorial guides you through pan sharpening Landsat imagery by combining the 15-meter panchromatic band with lower-resolution multispectral bands.

A pan sharpened Landsat 8 satellite image of Mount Jefferson in Oregon on the right with the unsharpened natural color image on the left. Images: NASA, public domain,

Pan Sharpening in GIS

Caitlin Dempsey

Enhance spatial detail in multispectral images with pan sharpening. Learn how this GIS technique combines data for sharper, more detailed satellite imagery.

A satellite image of islands.

Isostatic Rebound: How Earth’s Surface Rises after Glaciers Retreat

Caitlin Dempsey

Isostatic rebound is the Earth's slow rise after glaciers melt, reshaping coastlines, revealing landforms, and altering sea levels globally.

A satellite image of a cavum.

Cavum: Hole-punch Clouds

Caitlin Dempsey

Cavums are also known as hole-punch clouds or fallstreak holes.

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