I have an issue relating to the 'Expression String Builder'. I have a series of data over a 8 year period. I need to collect that data for only a 5 year period. Once collected I need to find the fishing intensity associated with pipelines. From figure 1 I need Dem11 to Dem15 (The figure shows a few pieces of data).
However I don't need Dem07 to Dem10. With this data I open up properties and create
rule-basedsymbology. The increments I require are
- less than 0
- 0 - 5
- 5 - 20
- 20 - 50
- 50 - 200
- 200 - 500
- greater than 500
Being new to QGIS, I thought the logical solution would be seen in figure 2.
This seems to work, but not very accurately.
Additionally, I need to do the same with 2 data sets e.g Dem11 to Dem15 & Nep11 to Nep15 together using the same increments. It doesn't seem to give accurate numbers whatsoever. e.g following the formula seen below Dem 11 to 15 gives me (26103 data points between 0 - 5). When I do the exact same with Nep11 to 15. I get (36051 between 0 - 5). However when I use the same formula as seen in figure 3 to add both together to find the fishing intensity I get (23448) which I not sure how is possible as this is 2655 less than the Dem11 to Dem15 data alone. Can anyone help me with my issue?