Posts Tagged ‘relief shading’

Scree Painter (Bernhard Jenny, ETHZ)

Monday, July 20th, 2009

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[Editor’s note: Bernhard Jenny, of the Swiss ETH in Zurich, has released a new software application for generating Swiss-style scree (rock) patterns for topographic maps. It fills user-specified polygons with scree stones. In years past, this technique was a very slow, time consuming manual process. Because of this, most modern maps have abandoned scree depiction or rely on out-of-date raster scans of old maps. This new stand-alone software for Mac, Windows, and Linux allows many GIS inputs like DEMs (DTMs) and settings customize the graphic treatment of dot size, density, and shape. Scree is useful for depicting mountainous areas, often rocky and devoid of vegetation. The rock pattern can indicate gullies and compliment relief shading for sunny and shadow areas by modulating the size and density of dots. Export is provided to PDF format. I hope we start seeing more scree on maps as a result of this software. Thanks Tom!]

Republished from ScreePainter.com.

Inputs and settings include:

Scree: the generated scree dots.
Scree Polygons: the polygons that are filled with scree dots.
Gully Lines: flow lines extracted from a digital elevation model.
Obstacles Mask: No scree dots are placed where this mask is black.
Shaded Relief: Modulates the size and density of dots.
Gradation Mask: Where this mask is dark, the contrast between bright and dark slopes is enhanced.
Large Stones Maks: Dots are enlarged where this maks is dark.
Reference Image: An image that is not used for generating scree dots. The reference image included in the sample data sets shows a map section with manually produced scree dots for comparison.

Read more and download application at ScreePainter . . .

New Global 30m DEM Topographic Data via ASTER (NASA)

Tuesday, June 30th, 2009

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[Editor’s note: NASA and Japan’s Ministry of Economy, Trade and industry (METI) released new 30 meter resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) to the worldwide June 29, 2009. The new dataset covers the high latitudes with increased precision over SRTM, although the cloud cover problems that plauge ASTER can prove problematic. The servers were being hit heavy on Monday and data download is convoluted. The preview of the data uses a curious data exploration color ramp with inverted shading. Thanks Tom and Laris!]

Republished from NASA.

PASADENA, Calif. – NASA and Japan released a new digital topographic map of Earth Monday that covers more of our planet than ever before. The map was produced with detailed measurements from NASA’s Terra spacecraft.

The new global digital elevation model of Earth was created from nearly 1.3 million individual stereo-pair images collected by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer, or Aster, instrument aboard Terra. NASA and Japan’s Ministry of Economy, Trade and Industry, known as METI, developed the data set. It is available online to users everywhere at no cost.

“This is the most complete, consistent global digital elevation data yet made available to the world,” said Woody Turner, Aster program scientist at NASA Headquarters in Washington. “This unique global set of data will serve users and researchers from a wide array of disciplines that need elevation and terrain information.”

According to Mike Abrams, Aster science team leader at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., the new topographic information will be of value throughout the Earth sciences and has many practical applications. “Aster’s accurate topographic data will be used for engineering, energy exploration, conserving natural resources, environmental management, public works design, firefighting, recreation, geology and city planning, to name just a few areas,” Abrams said.

Previously, the most complete topographic set of data publicly available was from NASA’s Shuttle Radar Topography Mission. That mission mapped 80 percent of Earth’s landmass, between 60 degrees north latitude and 57 degrees south. The new Aster data expand coverage to 99 percent, from 83 degrees north latitude and 83 degrees south. Each elevation measurement point in the new data is 30 meters (98 feet) apart.

“The Aster data fill in many of the voids in the shuttle mission’s data, such as in very steep terrains and in some deserts,” said Michael Kobrick, Shuttle Radar Topography Mission project scientist at JPL. “NASA is working to combine the Aster data with that of the Shuttle Radar Topography Mission and other sources to produce an even better global topographic map.”

NASA and METI are jointly contributing the Aster topographic data to the Group on Earth Observations, an international partnership headquartered at the World Meteorological Organization in Geneva, Switzerland, for use in its Global Earth Observation System of Systems. This “system of systems” is a collaborative, international effort to share and integrate Earth observation data from many different instruments and systems to help monitor and forecast global environmental changes.

NASA, METI and the U.S. Geological Survey validated the data, with support from the U.S. National Geospatial-Intelligence Agency and other collaborators. The data will be distributed by NASA’s Land Processes Distributed Active Archive Center at the U.S. Geological Survey’s Earth Resources Observation and Science Data Center in Sioux Falls, S.D., and by METI’s Earth Remote Sensing Data Analysis Center in Tokyo.

Aster is one of five Earth-observing instruments launched on Terra in December 1999. Aster acquires images from the visible to the thermal infrared wavelength region, with spatial resolutions ranging from about 15 to 90 meters (50 to 300 feet). A joint science team from the U.S. and Japan validates and calibrates the instrument and data products. The U.S. science team is located at JPL.

For visualizations of the new Aster topographic data, visit: http://www.nasa.gov/topics/earth/features/20090629.html .

Data users can download the Aster global digital elevation model at: https://wist.echo.nasa.gov/~wist/api/imswelcome and http://www.gdem.aster.ersdac.or.jp .

For more information about NASA and agency programs, visit: http://www.nasa.gov .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

Tóth Graphix Blog

Wednesday, March 4th, 2009

Tibor Tóth has been creating shaded relief maps (see examples below) for many years for National Geographic among others and has made himself a little blog talking about some of his projects to make the occasion of his seventy-second birthday.

Post topics include:

Continue reading to Tóth Graphix Blog . . .

Less is More – Don’t Default to Shaded Relief

Saturday, July 5th, 2008

montana map gene thorp wash post

My colleague Gene Thorp has a good map in today’s Washington Post showing land ownership in Montana near Missoula. The accompanying article by Karl Vick is headlined Closed-Door Deal Could Open Land In Montana Forest Service Angers Locals With Move That May Speed Building. (The Washington Post, July 5th, 2008.)

Here are the first two graphs of the story:

MISSOULA, Mont. — The Bush administration is preparing to ease the way for the nation’s largest private landowner to convert hundreds of thousands of acres of mountain forestland to residential subdivisions.

The deal was struck behind closed doors between Mark E. Rey, the former timber lobbyist who oversees the U.S. Forest Service, and Plum Creek Timber Co., a former logging company turned real estate investment trust that is building homes. Plum Creek owns more than 8 million acres nationwide, including 1.2 million acres in the mountains of western Montana, where local officials were stunned and outraged at the deal.

And another key graph:

That same impulse drives a different kind of land deal in the area: The buyers are the Nature Conservancy and other organizations that purchase desirable private land to preserve it. Since 2000, the groups have paid Plum Creek market rates to secure 280,000 sensitive acres in Montana alone.

When drawing maps of mountainous areas cartographers often get over-excited about adding relief shading to indicate the shape and height of the terrain in question. This is often appropriate for a reference map but on other maps the relief can be simply gratuitous.

When relief shading is not needed to understand the story and it may muddy the picture by creating distracting visual noise that interferes with communicating the map’s message. Just because the cartographer knows how to create the shaded relief or has a new wiz-bang data source or software program to do so does not mean relief shading should be added to the map.

By removing the relief from this map and choosing to show the Forest Service land in a muted olive green instead of glaring green, the red and black of the private land ownership pattern is allowed first visual prominence, thus strengthening and clarifying the map’s message.

Finally, the map’s message is clearly set forth in a prominent and clear legend. The map reader knows there are two primary and 1 secondary element to examine and compare on the graphic. A context map shows where in Montana the detail is located. Other features have been added for orientation, such as the Rocky Mountains label, Glacier National Park, and the call-out pointer box for Missoula.