I have a point layer with around 1.3 million features where one of the columns in the attributes table contains dates in the format YYYY-MM-DD.
Starting from an arbitrary date, say 2001-01-01, I would like to generate a series of maps which show all point features that have a date that is BEFORE that exogenously given starting date above and BEFORE every following month from then. In this example, I want to generate a map with all features before 2001-01-01, another one with all features before 2001-02-01, 2001-03-01 etc. Because I will have to generate many of such maps, I would like to automate this process.
To my knowledge, the atlas function will not do the job because it will iterate over each feature in the coverage layer. Also, I was not able to use the QGIS modeler with which I was hoping to make a selection by expression and then call the print composer.
I need to end up with the files map20010101.png, map20010201.png etc. saved to a folder for subsequent use. If that works via the print composer or not is not of importance.
Is there any functionality I was missing?
Software: QGIS 2.8.1, OS: MAX OSX
I have the same information in both, a string field and a date field. Making a selection works on the string field using the query builder, e.g. "date"<='2001-02-05', but not on the date field. The same applies to the Time Manager: The Time Manager works when I am using the string field, but not with the date field. However, that is not the problem for me. The problem is that the Time Manager makes "wrong selections" for my purposes, i.e. it selects observations that lie in intervals, e.g. "date">'2001-01-01' AND "date"='2001-01-31', but not "date"<='2001-01-01'.
