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Exploring Shaded Relief Techniques in Geographic Imager and Adobe Photoshop 3D

In the world of map-making, shaded relief refers to a visual technique that gives the illusion of three-dimensional terrain on an otherwise flat map. Cartographers use shaded relief to draw the viewer’s eye to prominent topographic features such as mountains, valleys and canyons. Using imaginary illumination sources and digital elevation data to cast directional light on a map, the cartographer can give the illusion of depth, casting shadows into valleys and lowlands, and highlighting ridgelines and peaks as if they are bathed in sunlight. 

Historically, this technique was achieved entirely by hand and was extremely labour intensive. Now, with modern graphical software and digital mapping technologies, relief shading can be accomplished right on the desktop. 

To demonstrate this, we are going to use the powerful spatial imagery tools and graphical design capabilities of the Geographic Imager plug-in for Adobe Photoshop to explore relief shading using a really interesting 19th-century historical map. Here is a sneak peek to show what the final product will look like.

Let’s start with our original map. We have taken an absolutely stunning United States Geological Survey Map of the world-renowned Grand Teton National Park in Wyoming. Originally drafted by hand in the year 1899, the map features beautifully drawn contour lines and colour work showing the mountainous topography of the park and its surrounding area. The map, and thousands of others like it, are available in full-resolution on the USGS Historical Map Catalogue. Our goal will be to bring the map to life using three-dimensional (3D) relief shading techniques available with Geographic Imager and Adobe Photoshop.

First, we need to bring in some elevation data. Elevation data is critical for creating shaded relief, as it determines how light and shadows will behave in different parts of the map. We can obtain high-resolution digital elevation models (DEM) for our region from the USGS EarthExplorer.

Those of your familiar with spatial imagery data and DEMs will know that our first challenge will be working with tiled (discontinuous) imagery data products. In its raw form, DEMs are often stored as identically sized tiles, with each tile representing a specific indexed region of the earth’s surface. It is an unfortunate reality that many times the spatial extent of each DEM tile rarely matches the exact extent of the area you are interested in mapping. As a result, map-makers and spatial imagery specialists need to implement tools to import, merge, and crop these tiles to a more useful format and size.

 

In our case, the elevation data for the area shown by the original 1899 topo-map is now represented by four separate DEM tiles, with roughly one tile for each quadrant of the map. To handle this problem, we can use the powerful Advanced Import tool within the Geographic Imager toolbar. The tool is a one-stop solution to easily import and mosaic our DEM datasets directly into Photoshop, all while retaining the spatial awareness we need to georeference or transform our data layers.

By combining each of the four raw DEM datasets, the tool will mosaic the tiles into a single merged, continuous, and geographically accurate elevation layer covering the entire extent of the map. Even more impressive is that Geographic Imager can use the spatial referencing information in the data to automatically align and overlay the original 1899 topo map onto the elevation layer, removing the need to perform manual georeferencing. (If the imagery data you are using does not have spatial referencing information already, don’t worry – our support team has crafted some excellent, easy to follow georeferencing in Geographic Imager tutorials).

With our DEM data imported into Photoshop, we can start to explore different techniques for creating shaded relief. We will start by using the Terrain Shader tool located on the Geographic Imager toolbar. Terrain shader is a one-click technique to create simple shaded relief instantly. It allows you to configure the angle and intensity of the simulated illumination source to control the prominence and direction of casted shadows. Additionally, you can apply customized colour gradients to easily produce stylized elevation maps or apply hypsometric tints. 

In many situations, the Terrain Shader tool is an all-in-one, quick and easy way to create shaded relief. The output of the tool makes it easy to distinguish topographic features and can be used to quickly produce a shaded-relief backdrop for your map.

One of the greatest benefits of using Geographic Imager is that we retain all the imagery manipulation and spatial referencing capabilities of a GIS while still having access to the massive inventory of powerful image editing tools provided by Photoshop. This allows us to take our shaded relief technique up a notch by incorporating the advanced 3D rendering and lighting tools of Photoshop 3D to truly bring our 1899 Grand Teton survey map to life.

To start, we first need to trim the DEM layer down to our specific area of interest. We used the GeoCrop tool to crop our mosaiced DEM layer down to the exact extent of our topo map (it is important that both layers are the exact same extent – you’ll see why later). Next, we can open up the Photoshop 3D toolbar, and convert our flat DEM into an extruded 3D “Depth Map”. 

To enhance the shaded relief effect, we need to apply a vertical exaggeration to the model. In 3D mode, we can drag the z-axis scaling slider to exaggerate the prominence of the topographical features in our map. By creating vertical exaggeration, we can create more pronounced shaded relief, as canyons and lowlands will capture shadows more effectively.

In 3D mode, we can use the mouse cursor to pan and rotate our “camera” to get different perspectives of our elevation model. This can be useful for creating orthographic or oblique perspective map styles.

Now that we have a configured 3D model of our map area, we can apply our simulated illumination source. Much like the Terrain Shader tool, we can control the illumination intensity and angle of approach. Since we are working in a 3D environment however, we now have three different axes that control where our light is coming from. Notice how the angle is important for affecting the length and intensity of shadows in our relief map. This includes the prominent mountain silhouettes that can be created when we set the light source to approach from a low angle on the horizon.

Next, we can configure the surface properties and apply a texture overlay to our 3D model. Experimenting with these settings changes how light interacts with the surface and can be refined to produce different relief shading effects. Using these surface properties, we can also drape the original 1899 Topo map onto our surface model (this is why it is important for both the DEM and the topo-map to share the exact same extent, otherwise the topo map will be distorted once it is draped over the surface).

Fine-tuning the map at this stage can take some time and experimentation. We can add some additional light sources with different casting angles and intensity to help create a multi-directional hillshade effect. We can also configure the light settings to produce softer, less pronounced shadows that look more realistic. After spending some time adjusting the lighting and surface settings, as well as configuring the camera view angle,  we can hit the “render” button and sit back while it creates a full-resolution rendering of our 3D model (this part can be very computationally intensive, and may require a high-performance machine to process efficiently).

Since we are still creating our map entirely within the Photoshop environment, we can immediately fine-tune the brightness, contrast, and colour of our map before exporting the final product. 

You can see some renders of the final map below. Thanks to the powerful spatial import and manipulation tools of Geographic Imager, and the ability to work entirely within the advanced image editing environment of Photoshop, we were able to create a dramatic 3D shaded relief effect that brings our 1899 USGS Grand Teton Survey map to life.

 

What’s New in Geographic Imager 6.3

Geographic Imager 6.3 - Avenza Systems

What’s New? Geographic Imager 6.3

We are happy to announce that Geographic Imager 6.3 is now available. This release brings continued improvements to compatibility with Adobe Photoshop 2021, and now offers full compatibility with the latest Mac OS 11 Big Sur release. We are also excited to introduce a brand new and easy way to access floating licenses directly from the cloud!

Here is what you can expect with the latest Geographic Imager 6.3 release:

macOS 11 Big Sur Compatibility

Users will be delighted to see that Geographic Imager 6.3 is now fully compatible with macOS 11 Big Sur. This means new and existing users can transition to the latest macOS without any interruption in their Geographic Imager capabilities.

Cloud Floating Licenses: A Better Way to Manage and Checkout Licenses

We have worked hard to deliver a newly improved floating license management system as part of Geographic Imager 6.3. This new license management system greatly improves on previous versions and allows users and administrators within an organization to efficiently and seamlessly access floating licenses directly from the cloud. The new licensing system is built on the RLM Cloud platform and means floating licenses can be implemented without the challenges of setting up, deploying, and managing a local server. Contact our Sales team to learn how you can set up your cloud floating licensing.

See the new cloud licensing options by accessing the license management panel within Geographic Imager 6.3

UXP Implementation for Chinese Versions of Geographic Imager 6.3

The Chinese version of Geographic Imager 6.3 now implements Adobe’s new powerful Unified Extensibility Platform. Which provides user interface improvements and flexibility to develop new tools in the future.

Geographic Imager Available Now

All active maintenance subscribers can upgrade to Geographic Imager 6.3 today for free. Users without an active maintenance subscription or on a previous Geographic Imager version can still upgrade.

 

Avenza Releases Geographic Imager 6.3 for Adobe Photoshop

 

Toronto, ON, February 22, 2021 – Avenza Systems Inc., producers of the Avenza Maps® app for mobile devices and geospatial plugins for Adobe Creative Cloud®, including MAPublisher® for Adobe Illustrator®, is pleased to announce the release of Geographic Imager® 6.3. This latest version provides full compatibility with macOS 11 Big Sur, and introduces a new cloud licensing system to efficiently access and manage floating licenses across an organization without the need to set-up, deploy and manage a local server. 

“Geographic Imager has built a reputation for providing a powerful suite of tools that seamlessly integrate into spatial imagery workflows built around Adobe Photoshop,” said Ted Florence, President of Avenza Systems. “By offering improved cloud licensing features and full compatibility with the latest macOS 11 release, Geographic imager continues to provide the productive, reliable user experience our customers have come to trust and rely upon”

Powering the Geospatial Imagery Editing Process

Geographic Imager for Adobe Photoshop® delivers an all-encompassing solution to import, edit, and export geospatial images such as aerial and satellite imagery. Work with digital elevation models, GeoTIFFs, and other popular GIS image formats while using Adobe Photoshop® features such as transparencies, filters, cropping, and image adjustments; all while maintaining georeferencing and support for hundreds of coordinate systems and projections.

New features of the Geographic Imager 6.3 plugin for Adobe Photoshop® include:

  • macOS 11 compatibility: Fully compatible with macOS 11 Big Sur
  • Cloud-based floating licenses: Access floating licenses easily with RLM Cloud
  • Chinese UXP update: Geographic imager 6.3 (Chinese Version) now uses Adobe’s new Unified Extensibility Platform (UXP)

 

Geographic Imager 6.3 is immediately available and free of charge to all current Geographic Imager Maintenance Program members and starts at US$349 for non-maintenance upgrades. New fixed licenses start at US$749. Geographic Imager Basic Edition licenses start at US$99. Academic, floating, and volume license pricing is also available. For more information, visit www.avenza.com/geographic-imager.

More about Avenza Systems Inc.

Avenza Systems Inc. is an award-winning, privately held corporation that provides cartographers and GIS professionals with powerful software tools to make better maps. In addition to desktop mapping software, Avenza offers the mobile Avenza Maps app to sell, purchase, distribute, and use maps on iOS and Android devices. For more information, visit www.avenza.com.

For further information contact:  416-487-5116 – info@avenza.comwww.avenza.com

Cartographer Chronicles: Robert Simmon

Rob Simmon for Avenza Systems

The visual portrayal of quantitative and qualitative data is a process that requires the right tools. You want your audience to be able to make sense of the data you are sharing and be able to weave that data into a compelling and inspiring story. Here is how Avenza MAPublisher and Geographic Imager assisted Robert Simmon, Senior Data Visualization Engineer at Planet.

Robert isn’t your typical data visualization engineer who had formal training in scientific graphic design or cartography. His passion and interest in computer graphics and a master’s degree in materials science gave him the technical skills to start turning numbers into pictures that eventually helped him communicate with research scientists in his professional career.

Robert’s stepping stone into the fields of cartography, design, and data visualization happened during his work at NASA, where one of his first projects was creating a CD-ROM that would allow students and the interested public to explore a global ozone dataset. During his work there, he began to realize that the graphics published and used by NASA were made more for other scientists than for a broad audience. He also realized that good design was a powerful tool to improve communication. So, he tried to re-create scientific graphics in a more user-friendly form, with mixed success. “It wasn’t until I attended a talk by a popular lecturer on visualization that I learned there was a theory behind good design, and a big lightbulb went off in my head,” says Robert. “I began to read everything I could get my hands on about design, data visualization, and cartography—particularly map projections and the use of colour to encode information, since so much visualization at NASA revolved around satellite remote sensing data, which is quantitative and inherently geospatial.”

Eventually, Robert went on to found the Earth Observatory to share the breadth of NASA’s Earth science research with the interested public. After more than a decade with NASA, he received the chance to join the exciting startup—Planet—and work with an unprecedented, high-resolution, global dataset.

Robert developed a fairly unconventional workflow centred around Adobe design tools rather than GIS or scientific visualization software. This is where the Geographic Imager plugin for Adobe Photoshop and MAPublisher plugin for Adobe Illustrator proved invaluable to bridge the gap between data and visualization.

Map created using MAPublisher and Geographic Imager by Robert Simmon

Today, Robert’s day-to-day work largely revolves around processing visible and near-infrared imagery. Every image he works with gets imported into Photoshop with Geographic Imager. Creating maps in Adobe has proven to be effective and highly efficient as software like Adobe Photoshop possess powerful colour-correction tools, fast previews, layers, high bit-depth support, and undo history options.

This aids highly competent visualizers to work seamlessly and flexibly until an image is made perfect. Robert uses Geographic Imager to merge multiple adjacent image scenes or align a time series to make an animation (even if they’re in different projections), all with a single “import” step. He then exports the file as a GeoTIFF, so the image can later be combined with other, complementary data.

Robert Simmon uses Avenza Plugins

Although Robert enjoys working with imagery, he has had the most fun combining multiple data sources, especially raster and vector. Delving into his design workflow a bit deeper, he involves both Adobe Photoshop and Illustrator together. In Adobe Photoshop/Geographic Imager he works on the initial colour work and crops his desired map extents, then imports it into Illustrator/MAPublisher to overlay with vector data and create masks. “It’s particularly useful to be able to crop the imported vector data to match the area of interest, rather than having to manually select and delete objects that lie outside the Illustrator artboard,” says Robert. After setting up his vector layers, he then exports them as a layered Photoshop file and re-combines them with the original raster imagery, to ensure pixel-perfect accuracy.

Data Visualization with Avenza Systems

Robert’s love for MAPublisher goes back to 2006 when he first used it to make maps with Landsat data. He used MAPublisher to create a water mask with ZIP code data, which was the only data source he could find with high enough resolution to accurately capture the jutting piers of lower Manhattan. Robert also used MAPublisher to create a map of Amazonia (one of his personal favourites from his portfolio) with the help of MAPublisher’s powerful attribute tools, which allowed him to select and merge data vector data of Amazon biome, distinct from the Political Amazon, for which data is readily available. He continued to create variations on this theme at Planet, including a map of the vegetation of Germany. It was derived from a Planet Surface Reflectance Basemap and given context with Natural Earth boundary, urban area, and transportation data.

Robert continues to tweak his colour palette for his vegetation maps since just being ‘good enough’ has never really been his forte.

_______

In collaboration with Robert Simmon, Senior Data Visualization Engineer at Planet.

Avenza Releases Geographic Imager 6.2 for Adobe Photoshop

Toronto, ON, October 21, 2020 – Avenza Systems Inc., producers of the Avenza Maps® app for mobile devices and geospatial plugins for Adobe Creative Cloud®, including MAPublisher® for Adobe Illustrator®, is pleased to announce the release of Geographic Imager® 6.2. This latest version is powered by Adobe’s new Unified Extensibility Platform (UXP), which provides tremendous performance and user interface improvements to the Geographic Imager plugin for Adobe Photoshop.

“Geographic Imager has become a product many organizations trust and depend on to quickly edit and process spatial imagery,” said Ted Florence, President of Avenza Systems. “With increased performance and even more opportunities to develop new tools and experiences with UXP, the possibilities are endless.”

Powering the Geospatial Imagery Editing Process

Geographic Imager for Adobe Photoshop® delivers an all-encompassing solution to import, edit, and export geospatial images such as aerial and satellite imagery. Work with digital elevation models, GeoTIFFs, and other popular GIS image formats while using Adobe Photoshop® features such as transparencies, filters, cropping and image adjustments; all while maintaining georeferencing and support for hundreds of coordinate systems and projections.

New features of the Geographic Imager 6.2 plugin for Adobe Photoshop® include:

  • Compatibility: Fully compatible with Adobe Photoshop® 2021 on both Windows and Mac, powered by Adobe’s new Unified Extensibility Platform (UXP)
  • Exporting: Vector map data is now able to export to many industry geospatial formats
  • Advanced Importing: Ability to remove backgrounds from images during import

 

Geographic Imager is immediately available and free of charge to all current Geographic Imager Maintenance Program members and starts at US$319 for non-maintenance upgrades. New fixed licenses start at US$699. Geographic Imager Basic Edition licenses start at US$99. Academic, floating and volume license pricing is also available.
For more information, visit www.avenza.com/geographic-imager.

More about Avenza Systems Inc.

Avenza Systems Inc. is an award-winning, privately held corporation that provides cartographers and GIS professionals with powerful software tools to make better maps. In addition to desktop mapping software, Avenza offers the mobile Avenza Maps app to sell, purchase, distribute, and use maps on iOS and Android devices. For more information, visit www.avenza.com.

For further information contact: 416-487-5116 – info@avenza.com – www.avenza.com

Cartographer Chronicles: Kim Beckmann

Cartographer Chronicles - Avenza Systems

Kim Beckmann is a storyteller above all else. As a graphic designer and Associate Professor of Design & Visual Communication at the University of Wisconsin-Milwaukee (UWM), Beckmann
uses visual media to do just that. More recently, she dipped her toes into the world of cartography (another story-telling medium) then fell right into the deep waters.

It all started when researchers from the university’s School of Freshwater Science came to her for help with creating supporting materials for a research project. The team’s ambitious project set out to map several miles of the Milwaukee harbor coastline, studying the effects of urban development on the harbor habitats. The research team had already created highly detailed technical maps but reached out to the Peck School of the Arts for a faculty member who could help put together the material in a way that could be more easily digested by the public and told the a story about the impact of people on the habitats that exist in the harbor.

“I also represent a part of the general public who would be interacting with the maps; individuals that want the maps to tell them a story. I recall at the first team meeting where we discussed research findings and what to present on the maps, I had many questions. What type of fish live in the harbor and rivers? What do they eat? Where do they live? Does water temperature effect where and when we might find them? Interestingly, the questions I raised led to incorporating additional habitat information into the maps,” said Beckmann. “What started as a concept for a single map quickly evolved to a set of five maps due to the amount to information we needed to share, the largest being 3 ft by 4 ft!”

Harbor Habitat - MAPublisher

As a graphic designer, Beckmann had made maps before, including simple, vector-based topographic maps, and maps for wayfinding. But this was her first time working on a larger map project and her first time working with raw geospatial data to create bathymetric maps to illustrate water depth. “I am extremely comfortable with Adobe Illustrator so when I discovered that there was a cartography plug-in for it, called MAPublisher, that could be used to manage GIS data to create maps, I knew that it would be faster and easier than learning an independent cartography software tool.”

The School of Freshwater Science research team carried out data collection for the project using side-scan sonar devices. With technical support from the Avenza Systems team, Beckmann was able to get the data into a shapefile format and import it into Adobe Illustrator using MAPublisher. “I registered for a training course offered by Avenza Systems, on how to use MAPublisher with Illustrator,” said Beckmann. “That led to a meeting with Jeff who was able to provide helpful direction on how to transform the raw map data into the maps I wanted to make.”

Data Progression - MAPublisher

Jeff Cable is the Desktop Product QA Lead at Avenza Systems. In addition to his work with the MAPublisher development team, he is also responsible for providing training to new MAPublisher users. “I met Kim in 2016 at one of our in-class training sessions in Chicago,” said Cable. “She had a very clear vision of what she wanted to create, but after some more discussion and reviewing the data, I realized that it would require advanced GIS workflows in order to get the data to an appropriate level before it was ready for mapping.” Seeing the value in the research project, he offered to assist Kim rather than have her seek out a GIS professional on her own. Once the data was prepared, she took what she learned from the MAPublisher training course and was able to apply visualization techniques to her maps. Cable corresponded several times as the project progressed and provided guidance. “Kim would ask if MAPublisher could do this or that, and in most cases, my answer was You bet it can!” he added. In addition to providing tips and best practices, he showed her many of the useful tools in MAPublisher that made her workflow more streamlined such as copying MAP Objects, working with MAP Stylesheets, and creating insets. “When I saw the finished product, I was blown away by what Kim had created. It was also gratifying as a training instructor to see how far she had come since our first meeting.”

Beckmann has since spoken about her work on the Milwaukee Harbor habitat maps project to the American Geographical Society, cartography clubs, and presented an artist talk as part of the Peck School of the Arts Artist Now! Lecture Series. The series of five maps have been printed on canvas and distributed to local and regional schools and turned into metal signage to be installed along the shores of the harbor to help share important research conducted by Janssen Labs with the public.

Fish Maps by Kim Beckmann using MAPublisher

The first of five maps installed at Harbor View Plaza Park.

Two of the maps installed in the active learning classroom as Discovery World.

Disovery World is located in Milwaukee, Wisconsin.

Beckmann’s maps also currently hang in the Avenza Systems offices and we are proud to have them as a reminder of the amazing things visual artists and cartographers can do with the tools we provide.

Learn more about the project and how the maps were made on the UWM website https://uwm.edu/harbormaps/

__________________

In collaboration with Kim Beckmann, Associate Professor of Design & Visual Communication at the University of Wisconsin-Milwaukee.

 

Updating and Enhancing Maps with Landsat 8

This guest blog post was written by Tom Patterson — one of the creators of the Equal Earth Projection, and Natural Earth Data, (you can read more about Tom here). Learn how he used Geographic Imager for Adobe Photoshop to create two maps from Landsat 8 imagery.

I am a big fan of Landsat 8 satellite images as a resource when making maps. Typically, I use these free images taken every 16 days for verifying and updating other geospatial datasets. I also transfer Landsat textures to shaded relief art in order to better evoke a sense of the physical environment.

The examples that follow demonstrate how I have used Landsat imagery to enhance two maps. The first example is Prince William Sound, Alaska, a map that I am presently working on. The second example is a Landsat mosaic of the Big Island of Hawaii. Both of my examples will give you a general idea on how to integrate Landsat images into your cartographic workflow—using Avenza’s GIS plugins for Adobe Photoshop and Illustrator—with a few technical tips thrown in for good measure. For in-depth information about using Landsat in Photoshop, refer to this tutorial.

Prince William Sound, Alaska

Prince William Sound, in south-central Alaska, is a spectacular place to map. Its sheltered waters are bounded by the lofty Chugach Mountains, indented by deep fjords with tidewater glaciers, and dotted by forest-cloaked islands. The problem I am facing is out-of-date geospatial data because of the rapidly melting of glaciers. For example, the positions of glaciers, lakes, rivers, and coastlines available in the National Hydro Dataset (NHD) have changed considerably since these data were collected between 2008 and 2012. In order to make an accurate map—if only for this year—I have had to re-digitize these vector elements using Landsat images as a reference.

For this task, I used “LandsatLook Images with Geographic Reference” downloaded from the Earth Explorer website. These quasi-natural color images, which come pre-made from bands 7, 5, and 3, clearly depict water bodies, vegetation, bare earth, and glaciers. They were perfect for mapping the changing landscape of Prince William Sound.

Tom Patterson Geographic ImagerNational Hydro Dataset lines overlaid on a LandsatLook image in Adobe Illustrator.
The lines do not match physical features on the more recent satellite image.

For reference, I used images taken on September 29, 2018, about the time when glacier melting ceases before the onset of winter. Images taken later in the fall are hampered by fresh snow cover and deep mountain shadows due to lower sun angles.

Because the LandsatLook images were in the same projection as my map, I could directly place and then register the images in the Adobe Illustrator file with MAPublisher. Had the projections been different, I first would have had to transform the LandsatLook images using the Geographic Imager plugin in Adobe Photoshop. Finally, I moved the LandsatLook images to a bottom layer and dimmed them for editing the lines with Illustrator’s Pencil tool. Using a Wacom tablet and stylus for editing lines greatly improved my drawing speed and accuracy.

If a 30-meter LandsatLook image lacks enough detail, you can increase the apparent resolution to 15 meters by applying panchromatic sharpening. Doing this will involve downloading all data bands that comprise the Landsat scene (a Zipped archive about 1 GB in size). Within this archive is Band 8, a grayscale image showing the same area as the LandsatLook image, but with double the resolution.

Tom Patterson Geographic ImagerComing into focus. A LandsatLook image before (left) and after (right) panchromatic sharpening.
Besides increasing detail, panchromatic sharpening also shifts colors.

Once Band 8 is downloaded, the first step is to enlarge the size of the LandsatLook image by 200 percent in Photoshop (Image/Image Size). Resample it using the Preserve Details (enlargement) option. Next, copy and paste Band 8 on top of the LandsatLook image. Then, in the Layers window, change the blending mode of the Band 8 layer from Normal to Luminosity. Finally, apply Curves adjustments to both layers until the tonal range of the combined image is to your liking. The pan-sharpened LandsatLook image will keep its georeferencing thanks to the Geographic Imager plugin.

Tom Patterson Geographic Imager Landsat8Use the Layers window in Photoshop to apply panchromatic sharpening. 
Selecting Luminosity blending mode for the Band 8 layer is key.

The Big Island, Hawaii

In 2017, I created a Landsat mosaic of the Big Island as a starting point for making two National Park Service maps: Ala Kahakai National Historic Trail and Hawaii Volcanoes National Park. I used the Landsat mosaic as a source for land cover textures—forest cover and historic lava flows (those that formed since 1800)—depicted on these maps. Compared to the Landsat mosaic, the map textures print very lightly in the interest of visual cleanliness.

Tom Patterson Geographic ImagerBig Island Landsat mosaic (left) and the maps of Ala Kahakai National Historic Trail (middle) and Hawaii Volcanoes National Park (right) derived from it. Click here to see a larger version of the Ala Kahakai map (5 MB) and here for the Hawaii Volcanoes map (6.4 MB).

The first step in creating a Landsat mosaic was downloading the appropriate image data. In a perfect world, a mosaic of the Big Island would only require four 185-kilometer-wide Landsat images. However, because of persistent cloudiness on the windward side of the island, ten images were needed to complete a nearly cloud-free mosaic. Using images taken in previous years was a necessity. When selecting older images with fewer clouds, I looked for those taken at about the same time of year to keep the lighting consistent. I then used the Clone Stamp and Spot Healing Brush tools in Photoshop to carefully delete any unavoidable clouds and their shadows from the mosaic. Fortunately, the few clouds that remained were in remote areas far from the main focus of the final maps.

Tom Patterson Geographic ImagerThe Big Island is covered by four overlapping Landsat images.

Tom Patterson Geographic Imager Landsat 8Clouds be gone. The Landsat mosaic before (left) and after (right) editing.

The Landsat mosaic was assembled in Photoshop using Geographic Imager (File/Automate/GI: Mosaic). In the Mosaic window, I selected the Maintain Layers option to ensure that each Landsat image was placed on a separate layer. I then added layer masks to each image layer to piece together the ten images with the goal of avoiding clouds. Although the masks themselves with feathered edges looked like a messy jig-saw puzzle, they combined to produce a seamless Landsat satellite image mosaic.

Tom Patterson Geographic Imager MosaicGeographic Imager’s Mosaic window.

I created the Big Island mosaic in natural color by compositing Bands 4, 3, and 2 as red, green, and blue channels, respectively, in Photoshop. I also brightened the forested areas with LandsatLook mosaic placed on the topmost Photoshop layer and with the layer opacity reduced (in normal blending mode). The natural color procedure is explained in detail here.

With a Landsat mosaic of the Big Island completed, my next task was extracting the forest and lava textures and applying them to the Ala Kahakai and Hawaii Volcanoes maps. But that was an involved procedure that will have to wait for another blog.

One more thing …

Since making the Big Island mosaic in 2017, the Puna district experienced volcanic activity in 2018 that covered a large area in lava and reconfigured the shoreline. Although Puna is the cloudiest area on the Big Island, I was lucky to find a recent cloud-free Landsat image that I then used to update the mosaic. You can download a GeoTIFF of the updated mosaic here (120 MB). It is in the public domain.

Tom Patterson Geographic ImagerPuna District, Hawaii, before (left) and after (right) the volcanic eruptions of 2018.

Cartographer Chronicles: Tom Patterson

The process of making maps can vary greatly depending on the cartographer and the purpose of the map. Tom Patterson, one of the cartographers behind the public domain data set Natural Earth and the popular website Shaded Relief, regards cartography as a creative process. He sees geospatial data as an artist would see paint on their palette. “They are raw materials from which the map is made,” says Patterson. “For me, the map making process starts with an online scavenger hunt for geospatial data, and ends with a visual depiction of the results of that scavenger hunt, a map.”

Patterson recently retired after 26 years with the U.S. National Park Service at the Harpers Ferry Center, located in West Virginia. Harpers Ferry Center is the media hub for the U.S. National Park Service, where most of the maps, exhibits, and publications for public consumption are produced.

Patterson is well-known for making maps with beautiful shaded relief effects, a technique that he has focused on for his entire career. It’s something he has a passion for and is a feature that he believes makes his maps unique. “When making a shaded relief, I go to great pains to portray the natural world in a beautiful and idealized manner, by combining shaded relief with land cover data, drop shadows, gradients and vignettes, with control and restraint,” says Patterson. “I ultimately want to create a shaded relief that readers will find attractive and which will blend harmoniously with the vector elements above.” Patterson prefers light, luminous colours for depicting terrain, and also tell a story. “A map is more than just a combination of points, lines, polygons, type and pixels. To me, a really good map is one that becomes much more than the sum of these parts,” he says. “Maps are an important form of communication, and they should effectively share the ideas of the cartographer to the map reader.”

When making graphically creative maps, you want to use tools that provide you with the most control. With MAPublisher, you can easily access and manipulate geospatial data using Adobe software. “MAPublisher and Geographic Imager bridge the gulf between graphical and GIS worlds.”

Patterson was an early-adopter of MAPublisher, a plug-in for Adobe Illustrator after learning about it in 1996 at the annual North American Cartographic Information Society (NACIS) conference. If you’ve ever used the Natural Earth data, you might be interested to know that most of the vector elements were created with MAPublisher and Adobe Illustrator.

He was also integral in the development of Geographic Imager when during a presentation about manipulating Digital Raster Elevation Model (DEM) data he commented that having a MAPublisher-like software for Adobe Photoshop would be useful. “My suggestion was heard by the President of Avenza, Ted Florence, who was in the audience. He put me in touch with the software development team at Avenza to brainstorm ideas about a GIS plug-in for Adobe Photoshop. Geographic Imager was the eventual result of our discussions.”

Along with his many contributions to the cartographic community, Patterson has held some important positions as the former president and current Executive Director of NACIS. Patterson has created accessible, open source data for global use (Natural Earth), he recently contributed to a new map projection that is taking the cartography and GIS world by storm; Equal Earth. “This equal-area pseudo-cylindrical projection has gained traction rapidly—it seems that cartographers and map users alike have had an unfilled need for world maps depicting countries at true size and presented in a pleasing manner,” he quips.

As an accomplished and respected veteran of the field, we asked that what advice Patterson would give to new cartographers, finding their way? “Seek out advice,” he states. “Map design and production is mostly a solitary task, and any map you create will seem easy-to-understand and logical to you since you are the one who made it. But, your readers may not see it that way,” says Patterson. “The easiest way to avoid these potential ‘failures to communicate’ is by showing drafts of your maps to people that are not family and close friends.”

Another tip that Patterson has for fledgeling cartographers, is to give readers a reason to slow down and read your map. “The trick in today’s media-saturated environment is to design a map that will catch your reader’s eye, ignite their curiosity, and draw them in. Give the most emphasis to the information you want them to remember long after they put down your map.”

Getting the Best Resolution when Importing an Image from a WMS

Using a Web Map Service (WMS) is a great way to easily get up-to-date imagery for your project. An issue you may run into, however, is that a server may not allow you to download images over a certain size (in pixels). The image resolution provided on most servers is usually high enough for most projects but there may be some instances where a higher resolution is needed (e.g. a poster-sized map or a web map that covers a large area).

One possible workaround for this issue is to get several small-area, high-resolution images from a WMS and then mosaic them together to make one large-area, high-resolution image. Here, we will use the City of Toronto Web Map Service to:

  1. Get an image of downtown Toronto
  2. Tile the image to split it into four smaller images
  3. Use the extents of the four tiled images to get four high-resolution images
  4. Mosaic the images to one large high-resolution image

 

Download an Image from the Web Map Service

First we will get an image of downtown Toronto from the City of Toronto WMS. Click the Advanced Import button on the Geographic Imager panel. Select Web Map Service from the Format drop-down and click Browse. Click Load services from Avenza and select City of Toronto WMS from the list.

 

Download an Image from the Web Map Service
(Click for larger version)

 

Select City of Toronto Imagery from the list of layers. Click Select Area then drag a box to zoom in on an area of downtown. Click OK to return to the previous window. There is no need to change the image size because we will use this image to get the extents of a higher resolution image. Leave the other options as default and click OK to load the image, and click OK again on the Advanced Import dialog box. The selected image will now open in Adobe Photoshop.

 

Tile the Image

Next, let’s tile the image to split it into four separate images. Open the Tile dialog box from the Geographic Imager panel. Choose By Number of Tiles as the Tiling Schema and change Horizontal and Vertical to 2. Change the Horizontal and Vertical Overlap to 3 percent. It’s important to have overlap between the images so they will mosaic properly when the data is transformed.

 

Tile the Image
(Click for larger version)

 

Click the Keep Images Open check box to enable it. Choose a name and location to save the tiles. You can save them to a temporary location because they will not be part of the final product. The four image tiles will open in separate tabs.

 

Estimate a Web Map Service’s Maximum Image Size

Open the City of Toronto Imagery WMS again and select an area. In this service, as with many other services, the maximum resolution is not provided. We can, however, use trial and error to find the largest image that the service will allow us to download. A WMS has a maximum allowed width and height set for an image request. The maximum width is usually the same as the maximum height.

Set the resolution of the image by adjusting the width of the image in pixels under Output Options. First, try setting Image Size to a pixel width of 5000. Height will update automatically based on the image’s dimensions. Click OK and you will see an error that says “Parameter ‘width’ contains unacceptable value” (or height if the images higher than it is wide). OK the error to close it.

 

Estimate a Web Map Service’s Maximum Image Size
(Click for larger version)

 

To estimate the maximum width and height allowed by a web service, you can adjust the image size to see when the server returns an error. The maximum width and height for the City of Toronto WMS is about 4000 pixels.

 

Downloading and Mosaicking Large Images

Next we will use the geographic extents of the four tiled images to download four higher resolution images with matching extents then mosaic the images together. Import an image again from the City of Toronto WMS using Advanced Import. Select an area, click Select Area by Another Document’s Extents and choose the first tiled image from the dropdown menu. The Select Area dialog will display an area matching that image’s area. Click OK to return to the previous screen.

 

Downloading large images
(Click for larger version)

 

Enter 3000 as the Image Size. Click OK to add the image to the Advanced Import dialog box. Repeat the above steps for each of the remaining three tiled images.

Creating a mosaic of four images (two by two) makes a single image just under 6000 pixels wide because of the overlap between the tiles (the height will vary depending on the area you selected). This is larger than the maximum size allowed by the WMS. Check the box Mosaic All Files to the Destination Document and select one of the images currently loaded in the dialog window from the drop-down menu. Leave the other options unchecked and select Normal as the Layer Blending Mode. This will merge the four images into a single document.

 

 

Mosaicking large images
(Click for larger version)

 

Avoid Downloading Images Greater than the Maximum Image Resolution

One further consideration when getting imagery from a service is to avoid requesting an image that is higher resolution than the full resolution of the image on the service. In this case, the number of pixels in the image and, therefore, the image size will increase without any increase in the actual resolution of the image.

To see an example of this, get an image from a WMS by zooming in on a small area and downloading images of varying resolution. The pictures below show two images of the same area side by side at different resolutions. The image on the left is 1024 by 870 pixels and the one on the right is 2500 by 2124 pixels but there is no noticeable difference between them. This is because the image exceeds the resolution of the image on the server so the WMS resamples the image to a higher resolution, creating duplicate pixels.

 

Avoid Downloading Images Greater than the Maximum Image Resolution
(Click for larger version)

 

Use Geographic Imager to Import Imagery from ArcGIS Online Directly Into Adobe Photoshop

With the latest release of Geographic Imager 5.2, it’s now possible to easily import images directly from an ArcGIS Online account or an ArcGIS web service. This will allow you to use shared data within your ArcGIS Online organizational account and connect to publicly available map servers from various online sources.

 

ArcGIS Online is a collaborative web GIS that allows you to store and share GIS data using Esri’s secure cloud. Before, you may have had to download raster layers to your local machine and then import them into Adobe Photoshop using Geographic Imager. Now, Geographic Imager has a much-improved workflow to get ArcGIS Online image layers into Adobe Photoshop with full georeferencing.

Currently, the types of datasets allowed are Map Image Layers and Tile Layers. To load a layer, open Advanced Import and select ArcGIS Online from the Format drop-down list. Enter the credentials for your ArcGIS Online account and select an image layer from your user portal.

Images can be resized and transformed on import. To extract a specific area from the image, click Select Area. The interface is the same as the one used for WMS Import.

In addition to using your own organization’s data, you can connect to publicly available data from a wide variety of organizations by connecting to an ArcGIS Web Service. To connect to a web service, use Advanced Import and select ArcGIS Web Service from the Format drop-down menu. Click Browse and enter the URL for the service. This is a great option when searching for data from open data portals created by government agencies.