Articles

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.

A meadow at Russian Ridge Open Space Preserve in the Santa Cruz Mountains with California poppies. Photo: Caitlin Dempsey.

Where Superblooms Occur in the United States

Caitlin Dempsey

Discover where superblooms occur across the United States, from California's deserts to spectacular spring wildflower displays across the West.

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.

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 soft color map showing the Antarctica ocean region and the path of an iceberg over time.

Geography and GIS Glossary

Caitlin Dempsey

This Geography and GIS glossary provides definitions for terms related to geographic information systems (GIS), cartography, remote sensing, and other ...

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.

Agricultural Patterns Visible from Space

Elizabeth Borneman

Satellite images reveal distinctive agricultural patterns shaped by history, geography, irrigation, and farming practices around the world.

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

How Much Forest Covers the Earth Depends on the Definition

Caitlin Dempsey

Forest cover estimates vary because there is no universal definition of a forest. Learn how canopy cover, tree height, and area thresholds affect global forest maps.

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

Learn how a deep-space satellite maps the height of Saharan dust, helping scientists improve weather forecasts and climate models.

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

Rapid shifts between extremely dry and unusually wet conditions are reshaping California’s fire landscape by increasing vegetation growth, drying fuels, and contributing to more intense wildfires.

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

Tampa Bay: Florida’s Largest Open Water Estuary

Caitlin Dempsey

Freshwater rivers and Gulf waters meet to create one of Florida's most productive coastal ecosystems, home to seagrass, mangroves, and diverse wildlife.

A Tweet from 2020 comparing a map to an animal.

Cartopareidolia: Seeing People and Animals in Maps

Caitlin Dempsey

Cartopareidolia is the tendency to see familiar shapes, animals, faces, and objects in coastlines, borders, and 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

Two mountain ranges and a central plain make Sado Island a classic example of tripartite geography.

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

What Are Glacier Grounding Lines?

Caitlin Dempsey

Grounding lines mark where glaciers begin floating, making them one of the most important indicators of ice sheet stability and sea-level rise.

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.

A black and a brown cow in a grassy pasture.

Mapping Methane: the Launch of MethaneSAT and the Limitations of Satellite Data

Caitlin Dempsey

While advances in remote sensing and satellite technology have improved methane mapping, ground measurements remain essential for accurate, localized data.

Map showing areas of increased artificial lighting in the Arctic, with increases in yellow, decreases in purple, and no change in green, using data from the U.S. DMSP satellites. Map: NASA, public domain.

Increased Light Pollution in the Arctic

Caitlin Dempsey

Satellite data reveals growing nighttime light levels across the Arctic, linked to expanding oil, gas, shipping, and infrastructure activity.

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