10 Replies Latest reply on Mar 17, 2014 7:49 AM by Nash Aragam

    Drawing a simple line graph...

    Nash Aragam

      Hi,

       

      Can anyone tell me why I can't get a simple continuous/discrete line drawing done with just two columns of an excel spreadsheet with Years (2008-2012) and Rates (0-140)? I have tried to convert the Year from "string" to "date" after discovering that Tableau read it as a string, but still no go! After conversion, I get a NULL for the year??? What's happening?

       

      TiA, Nash

        • 1. Re: Drawing a simple line graph...
          Matt Lutton

          It is very difficult to know what is happening without seeing the data or a packaged workbook.  I would suggest randomizing any sensitive information in the Excel file, pull that into Tableau as an Extract, and post the packaged workbook (.twbx file) here so we can see what you've done and provide advice based on that.  Cheers.

          • 2. Re: Re: Drawing a simple line graph...
            Nash Aragam

            Matthew,

             

            Thanks for the speedy reply... Here's the extract file attached...

             

            But I have a feeling that the problem might have to do with the file locks and/or handles....the directory from which I have been working is still in use and I CANNOT open this file in Excel any more. Tableau overrides something and tries to open a new workbook when I try to open this file in Excel. Would that tell you something?

             

            Nash

            • 3. Re: Re: Re: Drawing a simple line graph...
              Matt Lutton

              LineChart.png

              Thanks.  In the future, it is more ideal if you open this Extract in Tableau, complete the work you've tried to do (so we can see what you've tried to solve this problem), and post a Tableau Packaged Workbook file in the thread (.twbx file type--I have attached one to this reply, as an example).

               

              What you've attached is not an Excel file, its a Tableau Data Extract file, so it cannot be accessed from Excel. 

               

              I was able to connect to your Extract in Tableau and create a simple line chart as shown, by dragging the appropriate fields to the Column and Rows shelves and changing the Mark Type to "Line".  No need to convert the String to Dates in order to create this chart.   I hope this helps.  My version 8.1 workbook is attached.

              • 4. Re: Drawing a simple line graph...
                Tom W

                Note if you really wanted to convert this to a date, simply changing the data type will result in nulls because "2012" is not a valid date. You would need to create a calculated field which forms a correct date as follows

                mydate= date(datayr + "-01-01")

                • 5. Re: Re: Drawing a simple line graph...
                  Nash Aragam

                  Matthew,

                   

                  What I sent you was what you asked and I was NOT trying to open the *.tde (extract) file in Excel. Sorry if my last note conveyed the wrong info...

                   

                  In any case, thanks for making me realize that changing the visualization from a bar chart to line graph is by changing the "mark type"... I was using your "Show Me" to change the visualization and for some reason it is turned off (greyed out) but still allows me to click on it and end up in getting a NULL....is this a bug?

                   

                  Nash

                  • 6. Re: Re: Drawing a simple line graph...
                    Matt Lutton

                    Actually, I was requesting a Tableau Packaged Workbook file, but it doesn't matter at this point.

                     

                    "Show Me" assumes you are using specific data types, like a DATE--and as Tom suggested, "2012" is not a valid date.  You can convert the string to a date, using the calculation he described.  No bug.

                     

                    Best of luck.

                    • 7. Re: Re: Drawing a simple line graph...
                      Nash Aragam

                      Matthew, Tom,


                      Ah...it would be nice to warn users on using "Show Me" and its features and/or throw an exception about the use of proper conversion formulas, etc. Remember the whole idea of using Tableau and "point and click" visualization tool is for a NOVICE user and people who are not techies, but are far removed from the vagaries of any technical knowledge, but WILL use any tool that converts one visualization into another!

                       

                      Thanks much for the information...:)

                       

                      Nash

                      • 8. Re: Drawing a simple line graph...
                        Matt Lutton

                        Good luck as you move forward.  I think you'll find that Tableau is an incredibly complex piece of software and it will require many hours of experiential learning and discipline to become a solid developer.

                         

                        However, the good news is that you have this Forum available to you, as well as many other resources (including many blogs and sites on the Web) to help you navigate and learn the tool.

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                        • 9. Re: Re: Drawing a simple line graph...
                          Tom W

                          Nash Aragam wrote:

                           

                          Matthew, Tom,


                          Ah...it would be nice to warn users on using "Show Me" and its features and/or throw an exception about the use of proper conversion formulas, etc. Remember the whole idea of using Tableau and "point and click" visualization tool is for a NOVICE user and people who are not techies, but are far removed from the vagaries of any technical knowledge, but WILL use any tool that converts one visualization into another!

                           

                           

                          Tableau expects a level of structure and organization in the data. It tries to make a certain level of assumptions based on the data you feed it, but I don't think we're going to get to a point where you have the Microsoft style 'Clippy' sitting there saying "It looks like this is a date, do you want me to convert it?" or at least, I really hope not!

                           

                          Take the tech aside and use logic only, and we know that "2013" is not a date. When Tableau tried and failed to convert this, you saw the null error message and now you know this is your cue to look for errors in your data.

                           

                          My advice would be to always start in the table / text view. Prove your data is correct there before trying to apply visualizations as I can definitely appreciate how confusing it may be when you're starting out and you don't understand how / why the visualization has been produced the way it is. 

                          • 10. Re: Re: Drawing a simple line graph...
                            Nash Aragam


                            Well, I see that now....but then, the very idea of becoming a Tableau "developer" is oxy-moronic to me....it defeats the whole purpose of offering a point-and-click tool for complex data visualizations by managers, directors and political appointees in a context such as ours (state government). But then, that's a different argument altogether...

                             

                            For now, I am okay ... and I guess I probably would become the single point of contact for Tableau resource if it is to be deployed as a self-help tool for data visualizations across the division... I have been wrong to assume about the utility of data visualization tools available for a non-expert's use.

                             

                            Thanks much for your support,

                             

                            Nash