Constructing a “heat map” of the warehouse

A tool for visualizing warehouse activity

If you draw the layout of a warehouse within an MS Excel spreadsheet and label the storage locations, this program will color the map according to any table of data, such as historical frequency of visits. Figure 1 below is an example.

Figure 1: The darker storage locations were visited most frequently.

This can be used to display any location-based statistic, such as annual pick-lines, cubic volume of product removed, frequency of restock, weight of stored product, age of stored product, travel distance from shipping, etc.

Run it from here!

Please read the license and disclaimers, then click to launch the latest version via Java Webstart:

There is no charge for the use of this program.

If you are running the program for the first time, Java Web Start will download 9 program files totaling about 13MB to your computer. The next time you run the program Java Web Start will check for and download any upgrades before starting the program. If there have been no upgrades, the application will start immediately.

Recent changes to the Java security model and to the Georgia Tech server require you to give explicit permission to run programs from the Georgia Tech site. Here is how to do that:

This needs to be done only once: On PCs, open the Control Pane; on Macs, open System Preferences. Then, on either Mac or PC, select the Java Control Panel and click on the Security tab. and then on the button “Edit Site List”. Finally, add http://www2.isye.gatech.edu to the exception site list.

In addition, if you use a Mac, you will have to do the following each time you use the program: Go to System Preferences and select Security. Change the setting “Allow apps downloaded from:” to “Anywhere”. (Be sure to change it back after running the program.)

This works with all browsers except Internet Explorer, so you will have to use an alternative such as Firefox, Chrome, or Safari. And should the program not automatically start, locate the jnlp file in your Downloads folder and open it with Java Webstart.

(Some company firewalls may still prevent Java webstart programs from running, in which case see your system administrator.)

Need Java?

This program is written in Java so it runs on any brand computer and any operating system. If you do not already have Java installed, get the latest version of the Java Runtime Environment (JRE), which is freely available here:

Figure 2: The darker storage locations are closer to the pick-path and so more convenient.

How to use the program

1. Draw a map of the warehouse within a spreadsheet and label every section of rack/shelving with a unique address. Save the result in xlsx format (the newest MS Excel format), as in this example. (You need do this only once.)
2. Prepare a location-based statistic that you want to see, such as pick-lines per section of rack/shelving. This should be formatted as a tab-delimited text file with each line containing the unique address of one section of rack/shelving, followed by a tab, followed by the statistic of interest, such as this example, that lists the number of picks at each location during an interval of time.
3. Start the Heat Map program and follow the three steps (load the data file, choose the color scheme, color and save the map).

Tips

• The program colors a copy of your map. The spreadsheet that holds your warehouse map is not altered in any way and so can be used again later.
• The program colors only cells that contain an address that matches one in the data file. Nothing else is changed.
• Write the addresses of the rack/shelves exactly the same way in both the spreadsheet map and the data file. The program will treat “A-213-18” as a different address than “a-213-18”. Also, note that the program expects to find the addresses in the spreadsheet as text. It will ignore any entry, such as “21318”, that contain only numeric characters.
• Besides coloring the map, the program helps identify data flaws by listing any duplicate location addresses as well as any addresses in the data that are not found on the map.
• Here are some additional controls that you may find useful:
  • Click on the table headings of the input data (panel 1) to sort location addresses alphabetically or the statistic by size. One click sorts in ascending order; a subsequent click sorts in descending order; a third click returns to the initial sequence.
  • Control-click on the chart (panel 2) to copy, save, print, zoom or re-format it.

Remember that you can display any location-based statistic. Figures 1-4 show some examples.

Figure 3: This heat map shows all levels of the rack so that you can see not only where but how high the picks were during the year.

If you make an interesting map, please send us a copy!

You can find more information and tools like this in our textbook, at Warehouse & Distribution Science.

FAQ

Can I use some other spreadsheet program?

Yes, you can use any spreadsheet program that can read and write files in MS Excel xlsx format. Every spreadsheet that I know of can do this, including the excellent and freely available open source tools gnumeric, Calc (the spreadsheet in Open Office), and KSpread (the spreadsheet in KOffice).

The program changed some of the formatting in cells that it shaded.

Sometimes you may need to touch up the final result to ensure that attributes, such as alignment or orientation of text, are correct.

Why didn't you implement this using VB within MS Excel?

Because embedded macros in MS Office products are a rich source of viruses; because macros in MS Office can be excruciatingly slow; because MS Excel costs money and does not run on Linux and so some people do not have it.

Why can't I use xls-formatted files?

The xls format is a kludge of at least 3 other formats and so is temperamental and hard to write code for. In addition it supports only a subset of colors. The new xlsx format is cleaner, more robust, and supports the entire color space.

Figure 4: The shaded storage locations hold the oldest pallets and reveal how obsolete product is forcing increased travel.