Diagrams in an Online Course

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One of the courses I've been working on for a while is an upper-level engineering course. One of the "hidden" requirements is that students be able to provide sketches of problem scenarios. The idea is that a sketch can help students visualize an approach to a solution.

In a traditional course, the sketches are done in pen and pencil and handed in to the instructor. For an online course, it's different, because you have to digitize the images. So what to do?

Example Sketch

An example sketch might be something like the one below. If a pipe is .75 m, has an opening of 50 mm on one end and 85 mm on the other end, and the incoming water velocity is 3 m/sec, then what's the outgoing velocity? Here's the sketch:

ControlV.png Cylinder with arrow going in narrow end and another arrow coming out. Given measurements are labeled.

I should say that I was able to do this sketch reasonably quickly in a number of packages, but each of them required some learning especially for drawing lines and figuring out how to place the arrows. Also, to master these tools, you have to learn to navigate multiple pop-up windows. In other words, you have to be a little graphics saavy.

Vector Software

Engineering sketches lend themselves best to vector diagramming packages. My favorites so far have been:

Dia (Freeware/Windows)

If you're on the Windows platform, then the freeware Dia program may be a good answer for you. It does the basics (and that's all that's needed here), plus it has symbols of palettes just for technical types. What's also important is that it can export to other formats such as .png.

One quirk I found was that it tricky draw lines. As soon as you select the line tool, it starts a line (instead of you selecting a starting point). Fortunately, you can easily move the line. The other was that you had to right-click the line to find the arrows feature.

The following is a sketch produced by Dia.

Sketch in Dia

DrawBerry (Freeware/Windows)

A Mac version freeware sketcher is DrawBerry. It appears to be inspired by Dia, but it is not identical to it. It is also a 0.6 program and is subject to alpha behavior (including one crash) from time to time.

Other Freeware Packages

Listed on the Wikipedia List of Vector Graphics Editors Page

Gliffy (Web 2.0)

I've experimented with Gliffy.com, and it works well, but it appears that unless you get a "Pro" account, all images are open to the public. The base level is $5/month. Dia is cheaper and you can keep images or post them on the Web.

FYI - Photoshop.com looked interesting, but is not a vector drawing tool, so I wouldn't recommend it.

OmniGraffle (Mac Only)

If you want to pay some money, I do recommend OmniGraffle (and an early version may be installed on your machine). It's similar to Dia in that it's seemingly designed for technical types who just want to spit out a quick and dirty diagram.

Again, you can download specialized templates for free, and it has other features such as tool lines which quickly indicate how and objects are aligned. It is even better concept maps!

I would say that there is a little bit more of a learning curve because there are more features, but I don't think I could live without it. I wish I could say Microsoft Visio was the Windows equivalent, but it isn't.

Adobe Illustrator

The advantage of this is that it a professional level tool even though it is awfully quirky. For many simple diagrams though, this works just fine though (once you figure out how to "stylize" arrows). Another advantage is that there are plenty of online tutorials, and if you get a student discount, it could actually have a reasonable price tag.

I have to say that I feel like a user who needs more of a feature hit. If you have to have gradients, then you will be hooked on Illustrator. For the record, the diagram posted in this entry was done in Illustrator - it was the easiest to get "pretty".

Scan or Fax

Another answer is to either fax or scan a sketch...and I suspect some students will take us up on that option. The advantage is that you don't have to learn a software package, but you still have to upload the image. If you own a scanner, this will be fairly cheap. If you're a Penn State student, you may also be able to take advantage of lab scanners.

Faxing is easier, but probably more expensive. You either have to use phone minutes on your own fax or go to a copy store and fax (they charge per page).

A third option has been the Leapfrog Fly Fusion Pen which is a pen in which you write on special graph paper on a digital pen. The pen can store each page which you can upload to FlyWorld (yep a Web 2.0 service). It does work, but since I upgraded to Vista, FlyWorld keeps asking me to upgrade, but the upload became buggy.

A final scenario could be to use your camera to take pictures of an image, but can you deliver them to an instructor who may not want to incur the cell phone charges? You would have to extract them into some format.

Before I forget, there's also the Tablet PC option and the Wacom tablet option...which are great if you happen to own one of these.

Ultimately, we'll probably leave it to the student to decide how they want to deliver their digital sketches. I think they will be surprisingly resourceful.

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