This is part one of a three-part tutorial that introduces the basics of digitally drafting an underwater cave map using Adobe Illustrator.

A quick note

This tutorial is meant to act as a sort of tour behind the scenes for divers interested in cartography. It is not meant to be a complete Adobe Illustrator tutorial as there are already a number of excellent free tutorials online.

If you would prefer to start with a general purpose Illustrator tutorial, I can highly recommend the free beginners course by Gareth David Studio. The first video of his series is embedded below:

Introduction

Something that really helped me gain the confidence to start mapping caves was digitalizing other cartographer’s sketches. Mapping caves became much more approachable to me once I saw that even experienced cartographers made mistakes and their drawings weren't perfect. The sketch we will be using in this tutorial is one of my sketches from the Dos Palmas Cartography Project. It isn’t perfect either.

My main objective here is to give divers the opportunity to trace a map with as low of a learning curve as I can manage. There will be information missing, particularly with exporting the line survey, but that isn't the point of this exercise – we are just taking a tour. In future tutorials, we will go into greater detail and I think you will better understand those procedures by having done this short project first.

Note: I did clean up the scan on a few messy columns where it was difficult to see which line to trace. You can undo my fixes to see the original by expanding the Scan layer, and clicking the eye icon to the left of the sublayer titled, “Erased for clarity.” You may need to unlock the Scan layer first.

What do I need for the tutorial?

• Adobe Illustrator, free trial here.

• Desktop or laptop, preferably with a mouse.

• The tutorial file:

Quick facts

If you are already familiar with Adobe Illustrator, download the tutorial file above and use the Pencil Tool (N) to start tracing over the scanned drawing. Note: If you have an older version of Illustrator, use the included PDF file.

Draw the walls and columns in the w2d Walls shp sub-layer, and experiment with adding symbols such as depth, restrictions, and flow-direction into the w2d Detail sym sub-layer. Add your name, cave information, etc into the w2d Legend layer. The layer names apply to round-tripping which will be discussed in a future tutorial.

Feel free to try adding color to represent water in the w2d Detail shp sub-layer.

Illustrator Tutorial:
TRACING WALLS AND COLUMNS

• by Rory O’Keefe, November 13, 2020

The workspace

We first need to set up the Illustrator workspace so that your tool and panel options are in the same place as the tutorial screenshots.

Step 1: Open the project.

• Using Illustrator, open the tutorial file titled, Survey Down - Dos Palmas Map Demo.ai

• If you are using an older version of Illustrator that is not compatible with the included .ai file, open the PDF file with your version of Illustrator instead.

Step 2: Set the workspace.

• In the top menu bar, select Window > Workspace > Essentials.

For this tutorial we are using the default Essentials workspace but feel free to customize these settings to suit your needs as you learn the program.

In the above image, I have pointed out the main panels of the workspace that we will need for this tutorial. If you are not already familiar with Illustrator, please take a few minutes to click around on these highlighted panels.

If you accidentally change the workspace, you can reset it by going to Window > Workspace > Reset Essentials.

The layers panel

Layers are used to organize a project by separating different elements of a map into smaller groups that can be independently edited. For example, we will draw all of our walls in one layer, and add symbols such as the X used for restrictions in another layer.

The order of layers from top to bottom also plays an important role as the contents of one layer will appear above the contents of all layers below it. For example, when we add color to show that our cave is underwater, we want the color to be in the background of our map so that it does not cover the floor details. To do this, we would send the blue-coloring to the bottom of the Details Layer.

Note that there are two icons next to the left of each layer: an eye and a lock. The eye icon hides/unhides the contents of that layer but does not delete them. The lock icon locks/unlocks the layer. It is good practice to keep all layers that you are not actively working on locked.

Which layers do I use?

You may have noticed that the Illustrator file already contains two main layers, with many sub-layers. For this tutorial, we will work in the following three layers:

Layer 1:

• The drafting layer we will use to organize the digital copy of our map.

• Contains 11 sub-layers which can be further expanded.

Scans:

• The layer where we will keep the scanned underwater drawing from Dos Palmas.

• The scans layer can be hidden once we are finished tracing.

w2d Walls shp:

• The sub-layer we will trace all of the walls and columns in.

• Located by expanding the w2d Walls sub-layer within Layer 1.

All of the sub-layers play a role in round-tripping which will be discussed in future tutorials. Note that the funky names serve a purpose so leave them alone!

The tools we will use

Fortunately, since we are just tracing over a drawing, we only need to learn a few basic tools for this tutorial:

Selection Tool (shortcut, V):

• The general selection tool.

• Click on a blank section of the artboard to deselect an object.

• Hold alt while you click and drag an object to create a copy of that object.

Pencil Tool (shortcut, N):

• Used to trace lines over the walls and columns of the scanned sketch.

• Redraw over a line to make it smoother.

• To connect two lines, start drawing with a slight overlap of the line you want to connect into.

• We will use a stroke width of 1 pt, which can be adjusted in the Properties Panel.

Hand Tool (shortcut, H):

• Used to move the artboard around.

• Kind of like scrolling except in every direction instead of up/down.

• Press and hold the spacebar as a second shortcut option. Releasing the spacebar automatically goes back to your previous tool.

Zoom Tool (shortcut, Z):

• Used to zoom in and out of the artboard.

• In the top menu bar, go to View > GPU Preview to enable real-time zoom by clicking and dragging the mouse. Left zooms out, right zooms in.

Scissors Tool (shortcut, C):

• Used to cut a line.

• Click on the path of a line where you would like to cut it, then select and delete the off-cut.

Start tracing

Step 1: Check the survey alignment.

• The line-survey in the scanned image should be aligned with the blue line-survey in your illustrator file.

• If it is not still aligned, you may have accidentally moved it while playing around. Try to realign it by moving the scanned image or download the tutorial again for a new file.

• Note: There is a small misalignment near the bottom of the sketch because the survey has been updated since the sketch was made. This issue is fixed on the actual map and we can just ignore it for the purpose of this demo.

Step 2: Choose your layer.

• Check that you are in the correct layer, w2d Walls shp.

• To do this, unlock and expand Layer 1, then unlock and expand w2d Walls, and select w2d Walls shp.

Step 3: Zoom in.

• Sketch at a consistent zoom-percentage as it does seem to affect the smoothness of the lines.

• For this specific project file, I would trace at a zoom-percentage of about 1600% because I don’t have a very steady hand. This is my personal preference and you are welcome to use a different setting.

Step 4: Trace over the scan.

• Press N, or select the Pencil Tool and begin tracing all of the walls and columns.

• I frequently switch back and forth between the Pencil Tool and Hand Tool at this step to scroll – draw – scroll – draw – scroll, etc, until everything is traced.

• Make sure that your columns are all closed loops – this becomes important when we add color.

• Trace a small overlap of your previous line to automatically connect it to your new line. If this doesn't work you can select both of the lines with the Direct Selection tool (V), right-click and select Join. The shortcut for Join is Ctrl + J or Command + J.

• Remember that you can smooth lines by drawing over them with the Pencil Tool.

Step 5: Hide the scan.

• Click the eye icon next to the scan layer to hide the scanned image.

• With the scan hidden, you can check your work. Make sure that everything is on the correct layer, there are no unconnected wall lines (aside from open leads), and that all of the columns are closed-loops.

• Hide/un-hide the scan layer a few times to see if you catch any undrawn sections of the map.

Step 6: Save your work.

• Save the updated file for the next tutorial.

You’re finished… for now.

In future tutorials, we will add color to show the underwater passage, and add a cross-section.

If you’d like to continue playing around with the map, you can try the following:

• Add/create symbols in the w2d Detail sym sub-layer to show floor-to-ceiling heights, depth, restrictions, etc.

• Add your name, cave statistics, etc to the w2d Legend layer.

Feedback

This is the first time I’ve attempted to create an Illustrator tutorial so I would appreciate feedback on where I can improve, or if you’d prefer to see these created as videos rather than text.

I have intentionally tried to keep this tutorial simple, and we will eventually work through a complete cave map from start to finish, including the survey portion. Contact us.