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I've got a layer of polygons where each has a date associated with it. I want to color the polygons with graduated colors, but I want the colors to start with the newest polygons and fade to the oldest polygons. So far I haven't been able to find a way to do this in ArcMap (<= 9.3.1) other than to create a new field and calculate some integer or float value based on the date. Is it possible to use a date or time field directly?

  • The data is natively a date-time value
  • There are far too many records to use any unique-value renderer
  • Converting the date to a numerical field is an answer for a different question.
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I beleive range classification in Arcmap only works with numeric values but I could be wrong. –  badkins Apr 7 '11 at 12:10

4 Answers 4

I had the same question, and found myself here.

What I did is set a definition query to control the max date, date< '2009-01-01 00:00:00'

Then I can group the unique value symbology for anything pre-2009.

Then go back to the def query, extend the date range: date< '2009-01-01 00:00:00'

go back to symbology, add values and group.

repeat this process.

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Convert Time Field (Data Management)

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//0017000000v2000000.htm

Then use Time Animation

enter image description here

Then you can symbolize your data

Video http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Change_in_cropland_over_time

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The data is already in a time field, and unfortunately I don't have ArcGIS 10 to work with; however, is your method only for animations or will it allow one to symbolize a static map based on the date? –  dmsnell Apr 8 '11 at 16:38

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.

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Upvote. Good suggestion. I use this method a lot. If you use a larger numeric value type you can use a wider range of dates in some systems. –  Glenn Apr 7 '11 at 15:07

I'm not sure what version of ArcMap you are using, but with 9.3.1 if you go to the layer>Properties>Symbology tab, then select Categories>Unique values, and select your date field in the Value Field drop down. Next, select all of your date values using the shift key and pick a graduated color ramp in the Color Ramp dropdown. Yes, you cannot set a specific classification (e.g. Quantile) on your date field; however you can still symbolize your features in a graduated color fashion.

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