This question already has an answer here:

I need to create a thematic map for time intervals (ex. 1/1/1920-31/12/1929). To every polygon corresponds a date (from a date field) and I need them to be coloured depending in which interval they are situated. I can't find anywhere in the symbology tab a place to type the time ranges. In the quantities section I can't even select any field.

enter image description here

I would like to use Field calculator to convert my date into a number, which would represent the first year of a decade. For example 20/9/1954 ->> 1950. I think that would help me a lot. But I don't know how to do it in python or VB.

I have access to the Excel table that has been attached to the shapefile and I could easily do this transformation in Excel. And then add the data again to ArcMap. But I prefer doing it all this in ArcMap.

Another problem is that I have dates prior 1900, and if I sort them ascending, the ones before 1900 would appear even before the null values. So I guess ArcMap doesn't recognize them because of Excel. I've already read another topics about this problem, but I still couldn't find a solution.

I also read this answer to a similar question:

If you are looking for Quantities -> Graduated Colors/Symbols, they won't directly work with Date fields. You could however convert the date fields to numbers and use that instead. I'd convert each date to an Epoch timestamp (number of seconds since a particular date, 01/01/1970 being used most frequently), then use the Epoch timestamp to symbolize your features.

That would be very helpful too, but again, my lack of programming skills blocks me.

I solved this by extracting the year from the date field into a new field (integer) using field calculator and the formula: DatePart ("yyyy", [field.name] ). And then I created the map by quantities and used the intervals I wanted.

marked as duplicate by Chris W, Dan C, Mapperz Jul 18 '15 at 20:29

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 1
    What is the actual data type of your date field (open the attribute table, right click the field header, and choose properties)? If it's an actual date field or text, you can't use it with quantities - that only works for numeric fields. You'll have to convert the date field to a numeric to be able to symbolize in this manner. – Chris W Jul 18 '15 at 17:31

Try Categories -> Unique Values -> Value Field -> Your Date Field

  • 1
    The asker is looking to symbolize based on a classification / specific ranges of dates, not individual dates. The only way this method would work is if you then either manually group the desired dates into ranges and use symbol grouping or set the symbols for the dates in the same desired range to be the same symbology. In either case, it's a lot of manual symbology editing. – Chris W Jul 18 '15 at 17:34

Not the answer you're looking for? Browse other questions tagged or ask your own question.