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Visualize, Plan, Shoot!

How to use maps and apps to plan the images you imagine

When I’m helping a student set up a shot, I always ask three questions: “Have you refined your composition?” “What is your exposure strategy?” And, most importantly of all, “How could you make the best possible photograph of your subject?”

Image created by planning and previsualization.

This image taken near Columbine Falls, Rocky Mountain National Park, Colorado, is an example of a photograph that requires planning and precise timing to achieve a composition where the rising sun appears perfectly framed by the rock formation.

With that third question, I’m not asking what more the student could do at that moment. The first two questions largely address that task. I’m asking them to visualize possibilities that don’t exist at that instant. I ask, “What if you came back at sunset? What parts of the subject would be lit? Would the sun be in the frame? What if you returned at sunrise? What if you came back at the right time in the lunar cycle and stayed till the galactic center, the most photogenic part of the Milky Way, rose into a jet-black sky? What if you came back at an entirely different time of year, when the angle of sunrise and sunset will be radically different? Does the sun ever rise or set at a low point along the horizon, which would allow warm light to flood the foreground? Could the full moon ever play a prominent role in the image?”

Great landscape photographs often start with visualization—imagining the best possible image an interesting subject could offer. Sometimes the process begins at home with visualizing a compelling image, then going out in search of a place where that image could happen. Sometimes the process begins by studying maps to identify promising locations. And sometimes the process begins in the field with the discovery of a great subject, then continues by applying your knowledge of geography, atmospheric optics, local weather patterns and seasonal changes to envision the best possible image.

Image of the Milky Way over Lone Eagle Peak

Milky Way over Lone Eagle Peak and Mirror Lake, Indian Peaks Wilderness, Colorado.

In truth, these methods are interrelated. The first leads to the second, then the third and back to the first. However the process for an individual image starts, it ends with multiple visits to a great location until you capture the light and atmospherics that match your vision. With that photo in hand, the process repeats, as each shoot sparks fresh ideas for compelling images.

Using Maps To Help Visualize Photographs

Most often, I start my search for a great landscape photograph by studying a map, either on paper or on my computer screen. The USGS 7.5-minute quadrangles are the most detailed paper topographic maps available but must usually be ordered online. They typically have a scale of 2-5/8 inches per mile. The Trails Illustrated series of maps have a smaller scale (typically 1 or 1.5 inches per mile) but are readily available in most well-stocked outdoor stores.

The Photographer’s Ephemeris (TPE) is currently the best mapping application for photographers that will run on a desktop or laptop computer, as is also available for mobile devices. There are many other excellent mapping apps for mobile devices as well, such as PhotoPills and Sun Surveyor, but the map size is limited by the size of the screen. Maps are most useful when they are large, which is why I like viewing them on my 27-inch monitor. TPE comes in three versions: iOS, Android and desktop. The simplest desktop version ( is a free web app. The Pro desktop version has better maps, better location search and more features ($30 per year). All TPE screenshots in this article come from the Pro desktop version.

Sunset over Twilight Peaks

Sunset over the Twilight Peaks from Ruby Basin, Weminuche Wilderness, Colorado.

The heart of TPE is a topographic map. When the program opens, it displays a red primary marker on the map. Four thick, color-coded lines radiate from the primary marker, indicating the direction to sunrise (yellow), sunset (orange), moonrise (light blue) and moonset (dark blue) on the day you choose. If the sun is above the horizon at the time you’ve chosen, a thin yellow line appears, indicating the direction from the primary marker to the sun at that moment. If the moon is above the horizon, a thin blue line will appear, indicating the direction from the primary marker to the moon.

TPE also provides information on the time and azimuth of sunrise, sunset, moonrise and moonset, as well as data on the position of the sun and moon at any time of day or night. That information will help you visualize which parts of your subject will get sunrise or sunset light, from which direction (front light, side light or back light) and when.

The Pro desktop version adds broad light and dark gray lines, indicating the direction of the galactic center when it rises and sets, as well as a thin gray line, indicating the direction to the galactic center at the time you’ve selected.

Searching For The Position Of Celestial Bodies

Some landscape images only work if the sun, moon or galactic center appear in a precise location during a narrow window of time. For example, you might want to know when the sun will rise in the notch at the east end of Lake Isabelle in Colorado’s Indian Peaks Wilderness and bathe the foreground stream in beautiful light. Or you might want to know when the galactic center will appear in the notch to the right of Lone Eagle Peak as seen from Mirror Lake, also in the Indian Peaks Wilderness. Or you might want to know the best day to photograph the full moon setting over Longs Peak as seen from the summit of Twin Sisters in Rocky Mountain National Park.

Image of sunrise at Indian Peaks Wilderness

Cascade above Lake Isabelle at sunrise, Indian Peaks Wilderness, Colorado.

Today several smartphone and web apps can help you solve these problems. At this writing, the best position-search app for the sun, moon and galactic center is Sun Surveyor (iOS and Android—no desktop version). By the time you read this, the Pro version of TPE for desktop may also have sophisticated position-search capabilities. Let’s use Sun Surveyor’s position-search utility, combined with TPE for desktop, to determine the best day to shoot the full moon setting over Longs Peak from Twin Sisters at sunrise. You can then use the techniques you learn here to solve a wide range of problems involving the moon, sun and galactic center.

Images of the full moon rising or setting over some photogenic subject require careful planning because the moon is quite small in an angular sense, subtending an angle of only 0.5 degrees. To put that in perspective, the angle of view of a 35mm lens on a full-frame camera (measured on the long dimension) is about 54 degrees. Take a picture of the moon with a 35mm lens, and the moon will occupy only 1/108th of the width of the frame. Unless you’re blessed with an amazing sky, you need a long lens to magnify the moon and render it large enough in the frame to play a significant role in the composition. And if you’re going to use a long lens, then the moon must be low in the sky and close to the subject to include both the moon and the subject in the frame. One more tip: The earth rotates 360 degrees every 24 hours, which means that the moon (and the sun) move one degree across the sky every four minutes, or about one moon diameter in two minutes. If the moon is only one moon diameter above the actual horizon at the moment of sunrise, you’ve only got a couple of minutes until it begins to disappear.

Planning An Image Of The Full Moon Over Longs Peak

Example of an image that was preplanned using maps and apps.

The full moon setting over Longs Peak from the summit of Twin Sisters, Rocky Mountain National Park, Colorado.

With that as preamble, let’s figure out the best day in 2021 to shoot the full moon setting over Longs Peak from the summit of Twin Sisters. Start by opening TPE and searching for Twin Sisters Peaks. Activate the secondary marker and drop it on the summit of Longs Peak. Jot down the azimuth shown in the geodetics panel—the compass bearing from Twin Sisters to Longs Peak (Figure 1). Rounded, I get 245 degrees. You’ll want the moon, at sunrise, to have a similar bearing. The moon doesn’t have to be precisely over the summit of Longs to get a good photo; there’s actually a range of acceptable angles. Drag the secondary marker a bit left of Longs Peak and note the azimuth. Drag it a bit right and do the same. Let’s say the acceptable azimuth range is 235 to 250 degrees.

Screen shot from The Photographer's Ephemeris

Figure 1. Screenshot of The Photographer’s Ephemeris for desktop. The red primary marker is set atop Twin Sisters. the gray secondary marker is set atop Longs Peak. The bearing (azimuth) and elevation angle (altitude) of Longs Peak from Twin Sisters is shown in the geodetics panel (circled). The thin blue line from Twin Sisters to Longs Peak (partially obscured by the thin black line connecting the two markers) indicates the direction to the moon at 5:56 a.m. on April 27, 2021.

Twin Sisters is about 2,800 feet lower than Longs Peak, so you must look up slightly to see Longs’ summit. That angle, the altitude, is also shown in the geodetics panel. Rounded, I get 5 degrees. The moon must be higher than that angle for you to see it; any lower, and it would be hidden behind Longs Peak. Again, however, there is an acceptable range of values. Let’s say the acceptable altitude range is 6 to 10 degrees.

We have two final considerations: the percentage of the surface of the moon that will be illuminated and when the moon will appear within the acceptable range of azimuths and altitudes. We’re looking for a full moon, so a percentage illumination of 95 to 100 percent is appropriate. And we want beautiful light, so the range of acceptable times is from about 10 minutes before sunrise, when the twilight wedge usually peaks, until about 10 minutes afterward, when the warmth of the sunrise light will have largely faded. If you were shooting the full moon rising at sunset, you’d want a similar time range around sunset.

The beauty of Sun Surveyor is that it allows you to enter each of these search parameters as a range: azimuth, altitude, percentage of moon illuminated and time in relation to sunrise or sunset.

Open Sun Surveyor on your tablet or phone. Tap the menu icon in the top-left corner of the screen (the icon that looks like three horizontal bars). On the main menu, tap Settings. On the Settings screen turn on: Address Lookups, Elevation Lookups and North is True North. Turn off Quick Location Fix (Figure 2). All Sun Surveyor screenshots here are from the iOS version running on an iPad.

Screen shot from Sun Surveyor

Figure 2. Screenshot from Sun Surveyor showing the correct settings.

Now tap the menu icon again and choose Map. Tap the Location icon in the top-right corner of the screen (its appearance will vary depending on the device you’re using). Turn off Continuously Track My Location if it’s enabled, tap the search icon (the magnifying glass), then search for Twin Sisters Peaks. Tap “Twin Sisters Peaks, Colorado, USA” in the search results to set your location, and return to the Map module. Below the map, you’ll find the Info Carousel (Figure 3). Swipe left or right across the carousel until it shows Position Search, and tap the Position Search icon.

Screen shot of the Info Carousel in Sun Surveyor

Figure 3. Swipe left or right across the Info Carousel until it shows Position Search

Tap Moon on the next screen to open the search parameters screen. On the search parameters screen (Figure 4), choose a start date and time period to search. I chose Jan. 1, 2021, as the start date and one year as the length of time to search. Then I entered the other parameters we calculated above: 95-100 percent for illumination, 6-10 degrees for altitude, 235-250 degrees for azimuth and 10 minutes before sunrise to 10 minutes after sunrise. Sunset times are irrelevant for the moment.

Screen shot from Sun Surveyor

Figure 4. Screenshot from Sun Surveyor showing the parameters needed to search for the best day in 2021 to shoot the full moon setting over Longs Peak from Twin Sisters.

Tap Search (top-right corner) to see the results (Figure 5).

Screen shot from Sun Surveyor

Figure 5. Screenshot from Sun Surveyor showing the search results for the best day in 2021 to shoot the full moon setting over Longs Peak from Twin Sisters.

If you’ve entered your search parameters correctly, then every day in the search results will work, but you can use TPE to double-check and pick the very best day. Try the first date, April 27, 2021, at 5:56 a.m. Note that for each day in the search results, Sun Surveyor returns the first time when the moon’s position matches all search criteria. Enter that date in TPE’s date panel at the top of the interface. Drag the time slider on the chart to 5:56 a.m. A thin, dark blue line now extends from the Primary Marker—your position atop Twin Sisters—toward the moon at that moment (Figure 1).

Bingo! At 5:56 a.m., 10 minutes before the almanac time of sunrise, the moon will be directly above Longs Peak and just one degree (two moon diameters) higher than the summit of Longs Peak, so close to the horizon that you can use a long lens to magnify the moon. Longs Peak rises over 9,000 feet above the plains to the east, so the first light of sunrise will actually kiss the summit about 10 minutes before the almanac time of sunrise, which is calculated assuming the horizon is at the same elevation as the observer.

Sun Surveyor also lets you search for specific positions of the sun by entering an appropriate range for altitude and azimuth. And you can search for specific positions of the galactic center by entering a range for altitude and azimuth and specifying that the results only include periods between astronomical dusk and dawn with no visible moon.

Not every shot has to be visualized or even scouted. On rare occasions, I’ve stumbled across an exquisite subject just as the right light and atmospherics came together, then created a successful image of that scene. Far more often, however, my best images came about because I imagined them first and then found a way to put my vision onto my sensor. To me, visualization is one of the most exciting and enjoyable parts of landscape photography. Imagination is infinite—let yours run wild, then follow where it leads.

Glenn Randall is a wilderness landscape photographer whose primary subject is Colorado. He has been photographing every corner of the state since 1993 and recently completed a seven-year project to shoot sunrise from the summit of all 54 of Colorado’s 14,000-foot peaks. Farcountry Press published those images in Sunrise from the Summit: First Light on Colorado’s Fourteeners. Rocky Nook published his book Dusk to Dawn: A Guide to Landscape Photography at Night in spring 2018. The second edition of his bookThe Art, Science, and Craft of Great Landscape Photography, was published by Rocky Nook in spring, 2020.