A Collection of Round Islands

Several months ago I happened upon an island in Alaska called “Round Island.” I’d heard of other Round Islands elsewhere in the US, and I began to wonder just how many there were, and exactly how round they were. So, I decided to assemble them into a poster, for better appreciation of their numerousness and roundness (or lack thereof). I also expanded my search to include such islands in Canada, as well.

Round Islands.jpg


If you’re inclined, you can download a PDF.

This is an exploration of geographic forms. The forces of nature have constructed a variety of intriguing shapes, the aesthetics of which are just as important to a map’s appearance as the cartographer’s choice of color, typography, etc. I have sometimes browsed (and made) maps mainly to appreciate the particular shape of a coastline, path of a river, or some other geographic form.

I love looking at the variety and contrasts in this collection. Some of the islands are quite smooth, some are undulating and interdigitated. Some are quite round, while others are very poorly named.


This assemblage also highlights how inaccurate humans can be when naming features: many of these 131 islands are not very round. Maybe Long Island would be better for some of them. The lack of toponymic creativity is also noteworthy. In many cases, these identically named islands reside near each other within the same lake or harbor. I would be interested to see native names for these places, and whether they offer more interesting alternatives to the generic “(Sort of) Round Island.”

Each island is labeled with the coordinates of its center, as well as the body of water in which it is found.


As is usual with my side projects, I offer you some notes and observations:

  • I began by grabbing data from the US Geographic Names Information System and from Canada’s CanVec 1:50,000 Toponymic Features file.
  • There are a few places named “Round Island” which do not appear to be islands. Perhaps some of them were at one time, but have since been filled in. Whatever the reason, I only made use of those islands which were actually surrounded by water on all sides.

    Somewhat round, but certainly not an island anymore.

  • I traced these islands from aerial/satellite imagery. Given that we live in a world where coastline shapefiles exist, you may fairly ask why I might spend time doing something like that. The answer is that these islands vary a lot in size and in location, and I would have had to extract them one-by-one from a variety of different data sources. In many instances, the islands were too small to either appear in easily available shapefiles, or were far too simplified. So, it was probably faster to trace them, and it left me with the level of detail needed.
  • The shape and size of these islands varies based on tides. At low tide, more land may pop up out of the water. I had no consistent approach to this problem; I merely traced whatever it looked like whenever the image was taken. So, use this poster with caution if you are sailing in the vicinity of these islands. Shapefiles, I think, would not have helped much, since they’d be patched together from different scales and sources, so I would not have ended up with any consistency in approach.
  • Each of these islands is actually on its own projection, thanks to ArcMap’s Data-Driven Pages. I had it kick out a PDF, with one island per page. Each page was at the same scale, and each page was in a Lambert Azimuthal Equal Area projection with the standard point at the centroid of the island.
  • I did calculate the roundness of the various islands, but given the potential inconsistencies in tracing, tides, etc., I thought it best to avoid putting any such numbers on the map. I will leave it to the reader to judge just how round or not round any given island is.
  • The labels (set in Adobe Caslon) are all on a curve. I like it, but I can’t really say why I was inspired to do it. My colleague Nick Lally suggested that they give a sense of the movement of water around the islands. That explanation works for me, even if I can’t claim that it’s what I originally had in mind.
  • I played around with a different style for a while, involving various colors and hachures. I’m not sure why, but I initially felt like I shouldn’t make this grey. But getting the hachures to line up quite right caused me a bunch of trouble, and a highly scientific Twitter poll suggested that this style was the less-popular option. So, I decided to set them aside for now and go back to my standard grey waterlines.ColorHachure.jpg

This was a fun project to explore, and I hope you enjoy the fruits of my labor. Onward to the next random side project!

While I offer this project as a free PDF, it does take time and effort; if you derive some value from it, you are welcome to make a donation to support my continued work.

Creating Shaded Relief in Blender

Welcome! This is the long-awaited text version of my Blender relief tutorial, following on the video series I did a few years back. If you’ve already seen the videos and are returning for a refresher, note that I use a somewhat different method now, so don’t be surprised if you encounter unfamiliar settings.

This tutorial will take you an hour or two to get through — but I think the results are quite worth it. More importantly, note that your second relief will take much less time than this first one, since most of the work you’ll be doing can be saved and simply reloaded for future relief projects. Once you’ve invested the time to get comfortable with it, this technique can fit within ordinary production timelines.

Tutorials like this take a surprising amount of time to develop and maintain. This tutorial is, and will remain, free, but if you derive some value from it, you are welcome to make a donation to support my continued work.

Version History

Version 2.3 (Jan 13, 2022) — Edits to the last page, including a link to a discussion of how to make Blender relief look less Blender-y, and an updated oblique map.

Version 2.2 (Dec 05, 2021) — Blender 3.0 is now out. Significant revisions to screenshots. Discussed render performance earlier (as it bogged down for me earlier in the process). Denoising is now default, so I adjusted that section and removed a good chunk of it.

Version 2.1 (Oct 30, 2019) — Added step in Chapter 6 to change the heightmap’s color space, to avoid lowlands being washed out.

Version 2.0 (Sep 29, 2019) — Major revision for Blender 2.80. All screenshots replaced to reflect the new UI. Many steps rewritten to reflect new interface elements and new names for tools/features/menu items. Removed some no-longer-needed material, such as UV unwrapping, are no longer needed. Thanks to Diane Fritz for her notes on changes, which helped me double-check my work.

Version 1.2 (May 14, 2018) — Added new section in Chapter 7, pointing readers toward the idea of rendering relief on a pre-colored plane. Suggested by Anton van Tetering.

Version 1.1 (Jan 29, 2018) — Changes to Chapter 6: Added section on denoising, and alterered render settings to suggest using Limited Global Illumination. Both of these tips are courtesy of Dunstan Orchard.

Version 1.0 (Nov 16, 2017) — Initial release of text version.


Why Blender? In short: Blender makes better-looking relief. Most of the cartographers I know do their shaded relief in ArcMap or another GIS program, or sometimes they use Photoshop or Natural Scene Designer. All of these programs use basically the same algorithm, and you get a pretty similar results, as seen below. This standard GIS hillshade looks OK, but it’s rather noisy and harsh.


As Leland Brown has put it, this looks sort of like wrinkled tinfoil; full of sharp edges.

Blender, on the other hand, is designed specifically for 3D modeling. People use it for CGI, animations, and plenty more cool stuff. It’s intended to simulate the complexities of how light really works: the way it scatters, the way it reflects from one mountain to the next, and the way its absence creates shadows. Here’s Blender’s version of the same area:


Notice how it’s softer and more natural. The peaks cast shadows, and then those shadowed areas are gently lit by light scattered off of nearby mountain faces. Notice also how the structure of the terrain becomes more apparent. In a standard hillshade, I think you lose the forest for the trees. Here’s a side-by-side comparison of the two methods:


Blender’s result not only looks more attractive and realistic, it’s also more intelligible, I think. Certain features of the landscape become more apparent — look at the valley below, running northeast-southwest. It’s hard to tell how wide it is, or that it’s a valley at all, when looking at the standard hillshade. But the Blender relief makes its structure clear, thanks to the improved modeling of lighting.


Whereas the standard hillshade algorithm makes pixels lighter or darker based solely on which direction they’re facing, Blender looks at the scene’s context, and whether that pixel is in a mountain shadow or is in a position to catch scattered light. The result is a more attractive, more understandable relief.

Table of Contents

This is a fairly long tutorial, as I mentioned, so for your convenience I’ve split it up into multiple chapters.

  1. Getting Set Up: We begin by downloading Blender and preparing a heightmap
  2. Blender Basics: Here, we’ll learn to navigate the software
  3. The Plane: We shall set up a plane mesh and apply a heightmap texture
  4. The Camera: Let us prepare to image the plane correctly
  5. The Sun: In which we cast light upon the plane
  6. Final Adjustments: Here, lingering settings are finally adjusted
  7. Advanced Thoughts: For your consideration on future days

Please enjoy, and if you see any errors (either typographical or of fact), please do let me know. I hope that this tutorial empowers you to produce work you can be proud of!