Welcome to Layerscape. Session A. Motivation. Why should a Researcher be interested? Let’s assume that you want to do something around data visualization that goes beyond cool and arrives at useful Why should an educator be interested?
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For these formulas and any that follow: You may wish to cut the text from this PowerPoint presentation and paste it into the appropriate cell in an Excel spreadsheet. To paste: Right-click the destination cell and select Match Destination Formatting (M).
Select cells B2 through H2:
Double-click the little box at the lower right of the highlighted cells.
How the Excel Add In for WWT works, in three steps:
The next slides walk you through this process.
How it looks
You may need to manipulate the perspective to see your data (a sequence of white dots). Excel tries to take you to the first data point, which is west of Greenland.
Notice that in the Layer Manager in WWT this new data is given the name Sheet1_1. That name is a default provided by Excel which you can change to better describe the data.
We’ll do three things with the data visualization you’ve built thus far:
Suppose you want to know where a given data marker is in WWT. Excel supports this using Viewpoints.
Ok let’s pause to see the bigger picture for a moment. Session A is about mechanics; so granted the dataset is not too exciting. Once through this, however, session B will be about exploring multiple datasets in relation to one another in what we hope is an interesting way. This will require getting data from a variety of data providers on the web, then using our Excel machinery to bring them all into WWT.
Oblique view of data implying motion from north to south
Your first Tour slide will play back from your starting perspective. We have modified it to run for four seconds, and technically your Tour is done. But before we save it let’s add one more thing.
Before jumping in to more How To consider the task at hand as a challenge: How might you make a Tour slide that follows your data as it plays out in time as a flight path or trajectory?
The key idea is that slide Start Camera Positions and End Camera Positions encode WWT time values as well as spatial perspective.
Session A was a lot of stuff; so again congratulations on getting through it all!
In Session B we will explore the visualization potential of Layerscapein an Education setting. We will download a Tour and practice disassembling the data, then reassembling a new Tour from that.
In Session C we will follow a research arc: We pose some questions, choose one of them to try and answer, and then hunt down related data on the web and get a copy of it. From there we will see what is necessary to bring that data into WWT.
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Welcome to Session B. Here we will work more with Tours and Tour content (data) in the context of an Education session. We first remind you that the WWT menus are actually dual buttons: The text (“Explore”, “Guided Tours” etcetera) gives you one result when you click on it. The little down-arrow below the text gives you something else: A dropdown menu with many options. We indicate the main text menu using that text (“Explore”) and we indicate the sub-menu by appending a small v subscript to the text (“Explorev”).
Please begin by downloading a Tour from Layerscape (Save it as a file on your computer):
Open WWT and Explorev> Open > Tour… to load the above Tour in Edit Tour mode. To ensure you are Editing and not Viewing the Tour: Click on Guided Toursv. If the text “Edit Tour” is visible in the drop down list: Click it.
You can still watch Tours play back in Edit mode; but you can also Edit the Tour, which is what we want. This is an important detail to remember if you find yourself unable to edit a Tour!
Returning to the Excel spreadsheet: Notice that unlike in Session A there are no latitude or longitude columns. Rather each vector is represented as a row containing an entry like this:
That “LINESTRING((109…” entry is a format known as Well Known Text (WKT). For more on this see the Wikipedia article here:
Notice also that the column header for the WKT (Excel spreadsheet Column A) reads “geometry”. WWT interprets this to mean “Rather than latitude and longitude columns we will use WKT entries to provide position locations in this column.
Our example LINESTRING entries in WKT are triples separated by commas: First longitude, then latitude, then altitude. Notice this is a rather tricky “gotcha” if you happen to be accustomed to writing latitude then longitude.
This concludes our introduction to WKT and GEOMETRY. It expands our drawing capabilities in WWT beyond markers to lines; and we will visit a further extension to polygons in a later section of this workshop.
Notice that, like Markers, GEOMETRY objects can have color and date attributes (Columns B and C in the spreadsheet). They can also have a magnitude attribute but this has no actual effect on how the WKT objects are rendered.
Suppose you have the Vector Field loaded in WWT. You can imagine another WWT session that has a different data layer loaded, and so on; several data explorations. Let us next consider a “team project” where your goal is to build a single Tour from multiple source Tours.
The approach here is for you (and possibly your colleagues) to build individual short Tours around specific data layers. These layers might be recovered to individual source data files using the procedure outlined above for pulling the Vector Field from the large Tour. (Recall that was just one Layer of about 40 layers built into this Tour; some of which reside in a reference frame called ‘vk’.)
Once you have built several source Tours we will want to assemble a longer concatenated Tour; so this is the procedure we describe next.
With your Master Slide highlighted (yellow border; see image from previous page) click on “Text” at the upper right. This brings up a Text Editor.
Type in some text, like “Collaboration 101”, and click Save in the text editor. Your text now appears “stuck to the glass of the monitor” in WWT. (It is not “stuck to the earth somewhere”).
Drag the text to the lower left corner so it will not occupy the center of the frame. This text will persist throughout the Tour because it has been placed on a Master slide.
Right click on the Master slide, slide 0, and select Merge Tour after slide… You can now browse to and select one of your tours, T1.wtt. Do the same for T2 and T3, merging after the last slide of the Tour. You should now have concatenated your three Tours into one.
You can experiment with transitional frames between Tours, with adding explanatory text, adding shapes and illustrative pictures (again see the menu items at the upper right); and you can even add audio narrative and a background music file. The background music must be attached to a Master file so that it continues to play after the Master slide is done and the Tour continues to the subsequent slide.
This concludes Session B where we have covered
In Session C we will proceed to more of a “research/investigation” frame of mind to look for insight from data visualization.