כוון הציר האפקי במסמכים הנכתבים מימין לשמאל

Two screenshots: Arabic and Hebrew graphs

אני מחפש דוגמאות נוספות

יש לכם דוגמה של גרף עברי ״הפוך״? גרפים בערבית או פארסי? שלחו לי.

X-axis direction in Right-To-Left languages (part two)

Two screenshots: Arabic and Hebrew graphs

I need more examples

Do you have more examples of graphs written in Arabic, Farsi, Urdu or another RTL language? Please send them to me.

Textbook examples

I already wrote about my interest in data visualization in Right-To-Left (RTL) languages. Recently, I got copies of high school calculus books from Jordan and the Palestinian Authority.

Both Jordan and PA use the same (Jordanian) school program. In both cases, I was surprised to discover that they almost never use Latin or Greek letters in their math notation. Not only that, the entire direction of the the mathematical notation is from right to left. Here’s an illustrative example from the Palestinian book.

Screenshot: Arabic text, Arabic math notation and a graph

And here is an example from Jordan

What do we see here?

  • the use of Arabic numerals (which are sometimes called Eastern Arabic numerals)
  • The Arabic letters س (sin) and ص (saad) are used “instead of” x and y (the Arabic alphabet doesn’t have the notion of capital letters). The letter qaf (ق) is used as the archetypical function name (f). For some reason, the capital Greek Delta is here.
  • More interestingly, the entire math is “mirrored”, compared to the Left-To-Write world — including the operand order. Not only the operand order is “mirrored”, many other pieces of math notation are mirrored, such as the square root sign, limits and others.

Having said all that, one would expect to see the numbers on the X-axis (sorry, the س-axis) run from right to left. But no. The numbers on the graph run from left to right, similarly to the LTR world.

What about mathematics textbooks in Hebrew?

Unfortunately, I don’t have a copy of a Hebrew language book in calculus, so I will use fifth grade math book

Despite the fact that the Hebrew text flows from right to left, we (the Israelis) write our math notations from left to right. I have never saw any exceptions of this rule.

In this particular textbook, the X axis is set up from left to right. This direction is obvious in the upper example. The lower example lists months — from January to December. Despite the fact the the month names are written in Hebrew, their direction is LTR. Note that this is not an obvious choice. In many version of Excel, for example, the default direction of the X axis in Hebrew document is from right to left.

I need more examples

Do you have more examples of graphs written in Arabic, Farsi, Urdu or another RTL language? Please send them to me.

Useful redundancy — when using colors is not completely useless

The maximum data-ink ratio principle implies that one should not use colors in their graphs if the graph is understandable without the colors. The fact that you can do something, such as adding colors, doesn’t mean you should do it. I know it. I even have a dedicated tag on this blog for that. Sometimes, however, consistent use of colors serves as a useful navigation tool in a long discussion. Keep reading to learn about the justified use of colors.

Pew Research Center is a “is a nonpartisan American fact tank based in Washington, D.C. It provides information on social issues, public opinion, and demographic trends shaping the United States and the world.” Recently, I read a report prepared by the Pew Center on the religious divide in the Israeli society. This is a fascinating report. I recommend reading without any connection to data visualization.

But this post does not deal with the Isreali society but with graphs and colors.

Look at the first chart in that report. You may see a tidy pie chart with several colored segments. 

Pie chart: Religious composition of Israeli society. The chart uses several colored segments

Aha! Can’t they use a single color without losing the details? Of course the can! A monochrome pie chart would contain the same information:

Pie chart: Religious composition of Israeli society. The chart uses monochrome segments

In most of the cases, such a transformation would make a perfect sense. In most of the cases, but not in this report. This report is a multipage research document packed with many facts and analyses. The pie chart above is the first graph in that report that provides a broad overview of the Israeli society. The remaining of this report is dedicated to the relationships between and within the groups represented by the colorful segments in that pie chart. To help the reader navigating through this long report, its authors use a consistent color scheme that anchors every subsequent graph to the relevant sections of the original pie chart.

All these graphs and tables will be readable without the use of colors. Despite the fact that the colors here are redundant, this is a useful redundancy. By using the colors, the authors provided additional information layers that make the navigation within the document easier. I learned about the concept of useful redundancy from “Trees, Maps, and Theorems” by Jean-luc Dumout. If you can only read one book about data communication, it should be this book.

Microtext Line Charts

Why adding text labels to graph lines, when you can build graph lines using text labels? On microtext lines

richardbrath

Tangled Lines

Line charts are a staple of data visualization. They’ve existed at least since William Playfair and possibly earlier. Like many charts, they can be very powerful and also have their limitations. One limitation is the number of lines that can be displayed. One line works well: you can see trend, volatility, highs, lows, reversals. Two lines provides opportunity for comparison. 5 lines might be getting crowded. 10 lines and you’re starting to run out of colors. But what if the task is to compare across a peer group of 30 or 40 items? Lines get jumbled, there aren’t enough discrete colors, legends can’t clearly distinguish between them. Consider this example looking at unemployment across 37 countries from the OECD: which country had the lowest unemployment in 2010?

unemployment_plain

Tooltips are an obvious way to solve this, but tooltips have problems – they are much slower than just shifing visual attention…

View original post 1,323 more words

איך אומרים דאטה ויזואליזיישן בעברית?

This post is written in Hebrew about a Hebrew issue. I won’t translate it to English.

אני מלמד data visualization בשתי מכללות בישראלבמכללת עזריאלי להנדסה בירושלים ובמכון הטכנולוגי בחולון. כשכתבתי את הסילבוס הראשון שלי הייתי צריך למצוא מונח ל־data visualization וכתבתיהדמיית נתונים״ אומנם זה הזכיר לי קצת תהליך של סימולציה, אבל האופציה האחרת ששקלתי היתה ״דימות״ וידעתי שהיא שמורה ל־imaging, דהיינו תהליך של יצירת דמות או צורה של עצם, בעיקר בעולם הרפואה.

הבנתי שהמונח בעייתי בשיעור הראשון שהעברתי. מסתברששניים מארבעת הסטודנטים שהגיעו לשיעור חשבו שקורס ״הדמיית נתונים בתהליך מחקר ופיתוח״ מדבר על סימולציות.

מתישהו שמעתי מחבר של חבר שהמונח הנכון ל־visualization זה הדמאה, אבל זה נשמע לי פלצני מדי, אז השארתי את ה־״הדמיה״ בשם הקורס והוספתי “data visualization” בסוגריים.

היום, שלוש שנים אחרי ההרצאה הראשונה שהעברתי, ויומיים לפני פתיחת הסמסטר הבא, החלטתי לגגל (יש מילה כזאת? יש!) את התשובה. ומה מסתבר? עלון ״למד לשונך״ מס׳ 109 של האקדמיה ללשון עברית שיצא לאור בשנת 2015 קובע שהמונח ל־visualization הוא הַחְזָיָה. לא יודע מה אתכם, אבל אני לא משתגע על החזיה. עוד משהו שאני לא משתגע עליו הוא שבתור הדוגמא להחזיה, האקדמיה החלטיה לשים תרשים עוגה עם כל כך הרבה שגיאות!

Screen Shot 2018-10-23 at 20.35.52

נראה לי שאני אשאר עם הדמיה. ויקימילון מרשה לי.

נ.ב. שמתם לב שפוסט זה השתמשתי במקף עברי? אני מאוד אוהב את המקף העברי.

Data visualization in right-to-left languages

Line chart that uses Arabic text and numerals

If you speak Arabic or Farsi, I need your help. If you don’t speak, share this post with someone who does.

Right-to-left (RTL) languages such as Hebrew, Arabic, and Farsi are used by roughly 1.8 billion people around the world. Many of them consume data in their native languages. Nevertheless, I have never seen any research or study that explores data visualization in RTL languages. Until a couple of days ago, when I saw this interesting observation by Nick Doiron “Charts when you read right-to-left“.

I teach data visualization in Israeli colleges. Whenever a student asks me RTL-related questions, I always answer something like “it’s complicated, let’s not deal with that”. Moreover, in the assignments, I even allow my students to submit graphs in English, even if they write the report in Hebrew.

Nick’s post made me wonder about data visualization do’s and don’ts in RTL environments. Should Hebrew charts differ from Arabic or Farsi? What are the accepted practices?

If you speak Arabic or Farsi, I need your help. If you don’t speak, share this post with someone who does. I want to collect as many examples of data visualization in RTL languages. Links to research articles are more than welcome. You can leave your comments here or send them to boris@gorelik.net.

Thank you.

 

The image at the top of this post is a modified version of a graph that appears in the post that I cite. Unfortunately, I wasn’t able to find the original publication.

Graphing Highly Skewed Data – Tom Hopper

screenshot of three graphs: two bar plots and one dot plot with a split graph area

My colleague, Chares Earl, pointed me to this interesting 2010 post that explores different ways to visualize categories of drastically different sizes.

The post author, Tom Hopper, experiments with different ways to deal with “Data Giraffes”. Some of his experiments are really interesting (such as splitting the graph area). In one experiment, Tom Hopper draws bar chart on a log scale. Doing so is considered as a bad practice. Bar charts value (Y) axis must include meaningful zero, which log scale can’t have by its definition.

Other than that, a good read Graphing Highly Skewed Data – Tom Hopper

Sometimes, less is better than more

Illustration: cutting instruments: knife and scissors

Today, during the EuroSciPy conference, I gave a presentation titled “Three most common mistakes in data visualization and how to avoid them”. The title of this presentation is identical to the title of the presentation that I gave in Barcelona earlier this year. The original presentation was approximately one and a half hours long. I knew that EuroSciPy presentations were expected to be shorter, so I was prepared to shorten my talk to half an hour. At some point, a couple of days before departing to Trento, I realized that I was only allocated 15 minutes. Fifteen minutes! Instead of ninety.

Frankly speaking, I was in a panic. I even considered contacting EuroSciPy organizers and asking them to remove my talk from the program. But I was too embarrassed, so I decided to take the risk and started throwing slides away. Overall, I think that I spent eight to ten working hours shortening my presentation. Today, I finally presented it. Based on the result, and on the feedback that I got from the conference audience, I now know that the 15-minutes version is better than the original, longer one. Video recording of my talk is available on Youtube and is embedded below. Below is my slide deck

 

 

Illustration image credit: Photo by Jo Szczepanska on Unsplash