When trying to use LoadBuilder, the following error message occurs:
"Calculations returned the following error message:A very high number of Usage types were found. Please check whether the selected Usage type field is correct."
This is caused by an issue with the Type Field selected in LoadBuilder. For example "Load Type" for the Nearest Node method or "population density type" for the Load Estimation by Population method.
This error message indicates that there are a large number of distinct types in the selected "type" field. The type field should be a field in the shapefile that contains the label of the “type” of load or demand for the corresponding load polygon/point. For example residential, commercial, industrial. This enables you to enter a different pattern (for methods like nearest node) or projection (flow per capita per time, for methods like load estimation by population) for each of the different types. For example you might want to assign a specific pattern only to residential loads vs. industrial, or a provide a different projection of demand/load for each type.
So, there should be a relatively small number of distinct types in the field that you select, so that the list that you must populate isn’t too long (list of patterns at the end of the LoadBuilder process, or list of different projections to enter, for the projection methods). If you are seeing this message, that is usually an indication that you may not have selected the right field, or there is a problem with the field.
If you do not have a need to set a different pattern/projection for each type of use (only one pattern for all loads/demands for methods like nearest node, or only one projection to apply to all loads, for methods like Projection), then you would select the “<None>” option in the dropdown, which should automatically appear there. This will tell LoadBuilder that you don’t have a type field in your shapefile and that you will only have one pattern or projection for all loads.
If you do want to set different projections for different types of population, then you will need to either pick the correct field in the shapefile that has those labels, or you need to check the field you are trying to pick, for issues. If the field has similar but slightly different labels for the desired type for example, you may need to add a new column to your shapefile (via ArcGIS for example) to show only the unique types. For example if the label for a residential type looks like “Residential12345”, then the custom field could truncate it to just “Residential”. Or, if you have number codes to represent different types of loads, then you'll need to simplify it so there’s one unique number for each distinct type that you want to appear as a row in the table at the bottom of the LoadBuilder wizard.
In another case, this issue was resolved after recreating the ward boundary in GIS and applying back in Loadbuilder.
Related forum thread.
How do each of the Loadbuilder methods work?
Troubleshooting and Understanding LoadBuilder