Limitations to legend creation in Esri ArcGIS Pro pose significant obstacles for visualizing changes in climate data. ArcGIS Pro prevents users from specifying a minimum break below the range of their dataset, and modifications to the upper range are not used when constructing classes with equal intervals. The result is a legend with chaotic class breaks tied to the minimum value of each dataset. This is problematic when displaying climate data, where equal intervals representing the same ranges and class breaks across multiple maps are needed to visualize changes between emissions scenarios or time periods.
A second limitation is visualizing difference maps. These maps are typically centered on 0 and may extend different magnitudes in positive and negative directions. While ArcGIS Pro has built-in divergent color schemes, it is impossible to center them on your divergence value for rasters. Using the ‘critical break’ feature available for vectors does not balance the intensity of colors based on their distance from the divergence value, resulting in misleading maps.
LegendBrewer.org was created to overcome those limitations by allowing users to specify the minimum, maximum, and optional divergence value. It calculates equal interval legends using several methods and modifies colors and other styles while providing an instant preview. Users can then download a .lyrx file for rasters or vectors for use in ArcGIS software. While climate data motivated many of the features, it is broadly useful for quickly and precisely creating any equal interval legend.
To use Legend Brewer, enter the minimum and maximum values you want to use for your legend. If you are creating a divergent legend, you should also enter a divergence value. The legend will update in real-time as you make changes. Once you are satisfied with your legend, download the appropriate .lyrx file your data type (raster or vector) and import into ArcGIS Pro. It is possible to continue editing the legend in ArcGIS Pro, but some operations, such as changing class breaks, may not perform well.
If you know what you want your legend to look like, you can create a .lyrx file for it without uploading one. This is more reliable but may overwrite customizations you have added to your symbology.
Uploading and editing a .lyrx file is still under development and may cause unintended changes to your symbology. However, it tries to preserve as much of the uploaded file as possible. It will also pre-populate the fields Legend Brewer can modify with the values from the uploaded file.
Important: the .lyrx primary symbology must be set to the 'Classify' for rasters or 'Graduated Colors' for vectors before uploading.
By default, Legend Brewer will automatically select the number of classes and class size based on the values in the minimum and maximum fields. It will try to use round numbers and class sizes that are appropriate for your data, but it is just an approximation. You can increase or decrease the number of classes it produces, but if it is still not to your liking, use the 'Set legend class size' or 'Set the number of legend classes' methods for more percise control.
If you are making a divergent legend, the automatic method will force the divergence value to be in the middle of a class (e.g., a divergence value of 0 and class size of 10 will produce a class from -5 to 5). If you do not want this, either of the other methods will allow the divergence value to be anywhere within its class. Note that the tool detects when a divergence value falls on a class break and will use a color ramp that does not include a neutral color between the diverging colors.
Currently Legend Brewer only supports classified (graduated colors) equal interval legends. Many customizations, such as patch shape or outline color, are not modifiable in the tool. However, after a Legend Brewer .lyrx file is imported, most attributes other than class breaks can be modified in ArcGIS Pro.
Legend Brewer was developed and tested on a small sample of data. Unforeseen issues in .lyrx files created with Legend Brewer may cause ArcGIS Pro to crash. Please save and back up your work when using this tool. ArcGIS Pro will crash if you try to import a .lyrx file built for vectors to a raster (even if the .lyrx file was created with ArcGIS Pro).
Legend Brewer is not affiliated with Esri and is not responsible for any unintended consequences of using this tool.
If you find any issues or have feedback about Legend Brewer, please fill out this form.
Legend Brewer is named as an homage to the legendary Color Brewer. It uses color schemes from Color Brewer, but is not affiliated with it. Legend Brewer was developed by Ryan Noe with funding provided by U-Spatial at the University of Minnesota.