topic Re: Incorrect histograms of normalized variables in ArcGIS Pro in ArcGIS Pro Questions

Incorrect histograms of normalized variables in ArcGIS Pro

TomaszBartus — Tue, 12 Sep 2023 10:45:17 GMT

There is a known problem of very poor presentation of variable distributions in histograms in ArcGIS Pro. However, I did not expect that there were also such serious substantive errors.

ArcGIS Pro Ver: 3.1.3

Variable: AGE_50_64

Classyfication by natural breaks method (7 classes)

Normalization by POP_2000 variable.

Fig. 1. Normalized classyfication in ArcGIS DesktopFig. 2. Arc GIS Desktop histogram of the Fig. 1 populationFig. 3. ArcGIS Pro histogram the same normalized population as in Fig. 1

I suposse it is the serious application error.

Is there any other possible to make histogram of the normalized data in ArcGIS Pro (f.e. by Create Chart)?

Tomasz Bartuś

Re: Incorrect histograms of normalized variables in ArcGIS Pro

MervynLotter — Tue, 12 Sep 2023 10:56:06 GMT

Just right-click on the Census Tract layer in Contents pane, then go to Create Chart > Histogram. Then in the Chart Properties pane (that will open on right), select the variable to use under the Variable Number option.

Re: Incorrect histograms of normalized variables in ArcGIS Pro

TomaszBartus — Tue, 12 Sep 2023 11:21:08 GMT

Of course I know that. The problem is that there is no way to create histograms of normalized variables.
Unless there's something I don't know...
This is a clear step back from the excellent histograms available in ArcGIS Desktop.

Re: Incorrect histograms of normalized variables in ArcGIS Pro

MervynLotter — Tue, 12 Sep 2023 13:36:38 GMT

Sorry, I now understand.

Although not as simple as in ArcMap, you can still easily achieve this by opening up the Charts Properties dialogue box as discussed before, then on the far right of the Number drop-down option, click on the "Set an expression" button. Then in the Expression Builder simply double-click on the field Age_50_64, then divide (backslash) and then double-click on POP2000. This will create a histogram with the normalized data you are looking for.

Re: Incorrect histograms of normalized variables in ArcGIS Pro

TomaszBartus — Tue, 12 Sep 2023 14:37:35 GMT

Thank you for the good advice. Of course it worked. The histogram of the normalized variable (Figure 4) is very similar to Figure 2.

Fig. 4. ArcGIS Pro histogram of the normalized AGE_50_64 variable

However, the question remains why ArcGIS Pro draws such nonsense as in Fig. 3???

Regards

Re: Incorrect histograms of normalized variables in ArcGIS Pro

MervynLotter — Tue, 12 Sep 2023 14:53:36 GMT

The coloured line and histogram in Figure 3 is based on the Natural breaks classification that you chose. Try changing the classification method to Standard Deviation. The purpose of their "histogram" is to help find the necessary symbology breaks and how these may impact on the data when visualised on a map.

Re: Incorrect histograms of normalized variables in ArcGIS Pro

TomaszBartus — Wed, 13 Sep 2023 07:27:51 GMT

OK, but the distribution of such a large population and close to normal should in no way be illustrated with two bars. This is an obvious software error. Let's leave the topic aside because I don't do research, I only prepare exercises for students.

Thank you very much for your help.

Greetings from the sunny Kraków.