I have a question about something which I think is possible but just can't get my head round it, and haven't found any answers online. I'm using $id= @atlas_featureid in QGIS 2.14 to create an set of images from the Atlas tool, and it works fine as usual. However, instead of having each map iterate through the dataset and show one row of data at a time, I'd like it to show one row of data and then add each row of data successively in a cumulative way. I think I can use a rule to achieve this, but not sure how.

Example image: https://2.bp.blogspot.com/-326CYkmBxH0/WOUFwYzYv6I/AAAAAAAACIk/bzgu-84DcX8QR23zFItNF2lZXnUGE7SqQCLcB/s1600/gun_homicides_cumulative_2015_100ms.gif

Individual Atlas extract - one day = one map. enter image description here

To help explain, see this gif I created from a series of maps on US gun crime. Instead of one day's worth of data appearing at a time, I'd like it to build up over time so that on the Jan 31 frame there is 31 day's worth of dots on screen and then it's just a mess of dots by Dec 31 - I know it will probably look bad but I'd like to use it in other projects as well.

Does anyone know how this could be done?

Just putting into an answer @iant comment, that solved the problem

If you use

$id= @atlas_featureid

you will display the current entity.

However, if you use

$id <= @atlas_featureid

you will display the current entity + the previous ones in a cumulative way.

Your Answer

 

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

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