Set symbology’s lower value manually in ArcGIS PRO

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08-21-2020 06:25 AM
Status: Open
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CordulaGöke
New Contributor III

Lower class value of the lowest class cannot be manually changed (it was the same in ArcGIS).

You can update by choosing advanced-> sample size-> set sample size up, if you have not chosen “manual interval”. If you have chosen “manual interval”, not even that will work. If you realize too late that not all your data is covered or want to import symbology, there is no way around to set all class values manually again. There is no option only to update the lower value. The new sampling will always change the class values based on the chosen method and the new histogram.

You can actually set the upper value of the first class lower than the automatically estimated lower value. This is different from ArcGIS and changes the situation from being annoying to being a bug.

The new thing is that you can add “out of range” as a new feature in pro, but again the same, there is no way to update the range once you are in manual interval, you can change the upper value for the lowest interval, but the data will be shown as out of range and that is wrong and a bug.

The preferred solution is to be able to set the lower value manually, than you do not need to update with large samples and you can prepare the symbology for possible future lower values in dynamic data. Additionally, it would be easier to move the sampling from the advanced to the histogram-menu.

In the example I imported symbology from another layers based on latitude onto the column longitude. It is completely out of range, but normally I would want to keep the class limits. I calculated the statistics for the lon column in the table and then chose an upper value which definitely lies in the range of Lon. I added out of range symbols, otherwise the map would be simply white. The points would not be selectable. Choosing to update the range during support would change all class limits when anautomatic classification was chosen in the original layer and not update when "maual interval" is chosen.In the example I imported symbology from another layers based on latitude on the column longitude. It is completely out of range, but normally I would want to keep the class limits. I calculated the statistics for the lon column in the table and then chose an upper value which definitely lies in the range of Lon. I added out of range symbols, otherwise the map would be simply white. The points would not be selectable.

5 Comments
RyanCoodey

In Classified Renderers, when manually setting the "Break Values", you can set a break greater than the maximum statistic, but you can NOT set a break lower than the minimum.  It forces you to the value of the minimum statistic.  What if you have data that might go lower than this in the future?  What if you just want to set nice clean breaks?  I don't see why the smallest break must be greater than or equal to the minimum statistic.

This can be gotten around by loading values from another data set, but this is a lot of extra work to setup that data as needed.

PhilippMarty
In ArcMap: If you want to set break values manually during a classification, the minimum break value is not allowed to be smaller then the datas minimum value. Of course there is a work around (--> import a predefined lyr-file), but it would be helpful to define the minimum break value without the mentioned limitation.
CordulaGöke

The same applies to classified symbology for vector data. At the moment it is in ArcGIS Pro even possible to set the upper value of the first class lower than the range that ArcGIS automatically calculates. The lower value does not get changed in this process. Connected to this is the option to recalculate the range with higher sample size. This option should be moved from advanced to the histogram menue. If you have already chosen manually changed classes, the lower value will not update, so you have to change back to one of the automatic class options and manually enter the ranges afterwards. Also for importing symbology from .lyr does not offer the option to adapt the lower value to the class range in the current data.

CordulaGöke

Today I learnedthat it is possible to text edit the *.lyrx. So if I take the step to export to lyrx, it is actually possible.

ChelseaRozek

First time running into this issue for me. Surprised to see this idea from 2010. More than 10 years later, Pro can't do this. I'm trying to make a COVID-19 vaccination rate map with graduated colors. They want a set of colors each 10% from 0-100% so we can compare maps over time. I can't set an interval range for lower than our lowest vaccination rate.