QGIS » QGIS Application

I closed qgis, removed the .qgis2 directory, and started it back up. The heatmap started working again at default settings. So I gradually bumped the heatmap down and down until I got to 500 meters, and I was still getting meaningful information. Only when I checked Advanced and changed the Rows field to 1500 (I let Columns scale proportionally) did I start getting the bad heatmaps. Unchecking Advanced does not fix this.

BTW, I am on c8d3fa7.

Can you share the source layer you are using for this?

It's a PostGIS layer, but QGIS won't let me export it due to #8101.

Would you take an SQL export of a PostGIS 2.0/Postgres 9.2 table?

Aren Cambre wrote:

Would you take an SQL export of a PostGIS 2.0/Postgres 9.2 table?

yes thanks, so we can test also the other issue.

Well, this is weird.

• integer (ID column)
• data
• time without time zone
• character varying(10)*
• character varying(4)*
• integer
• integer*
• boolean
• geometry(Point, 3081)

\\*Was used to filter the dataset.

Then I further restricted the dataset by removing all columns except id and geom and only including rows that match the query, so the resulting, unfiltered dataset has 2 columns and 9874 rows. The heatmap works now, but the related issue (bug #8101) remains broken.

Why am I talking about this? There's a lot of the data that, for complex reasons, I cannot disclose. In the process of stripping the data down to both a manageable dataset and the portion thereof that I can disclose, I seem to have eliminated the problem. It's almost as if there's something about the presence of these other columns or many unfiltered rows in the original data that's tripping up the Heatmap plugin.

Aren Cambre wrote:

Well, this is weird.

I've modified my dataset by combining 3 similar ones and reducing the number of columns. So instead of 148-170 columns (depending on which year's data you're looking at), I merged the 3 datasets into one table with 9 columns. I loaded that, applied the filter, and got the same problem. The columns were of type:

• integer (ID column)
• data
• time without time zone
• character varying(10)*
• character varying(4)*
• integer
• integer*
• boolean
• geometry(Point, 3081)

\\*Was used to filter the dataset.

Then I further restricted the dataset by removing all columns except id and geom and only including rows that match the query, so the resulting, unfiltered dataset has 2 columns and 9874 rows. The heatmap works now, but the related issue (bug #8101) remains broken.

Why am I talking about this? There's a lot of the data that, for complex reasons, I cannot disclose. In the process of stripping the data down to both a manageable dataset and the portion thereof that I can disclose, I seem to have eliminated the problem. It's almost as if there's something about the presence of these other columns or many unfiltered rows in the original data that's tripping up the Heatmap plugin.

Can't you apply and undisclosed (or random) shift to your points and fill the columns with random junk and then share the dataset?

Got it! Can you email me directly at [email protected]? I'd like discuss transferring the data outside this issue.

Nyall was able to replicate the issue. (He told me over email instead of posting here.)

He has a proposed fix, although it looks like I'd have to compile, and it may be a few days before I can get around to that unless his fix can be pushed to master. I can refresh master using osgeo4w.

Proposed fix is here:
https://github.com/nyalldawson/Quantum-GIS/commit/8d7a686a86961e1642176d91ad3a883b8b92d3b7

I'm going to double check it and run it through some more tests before committing.

Nyall, what happens when you press Zoom to Layer after applying my provided filter to that layer? If it doesn't zoom to fit that layer on the screen, then you may be another person to reproduce #8192. It would be interesting to see your findings.

I've merged this fix to master for further testing -- would appreciate some feedback if this fixes the issue!

What daily release of master is this in? I'm on f4ac684 and don't see a change.

It should hit the osgeo4w build today - f4ac684 doesn't have this fix applied.

Just updated to b1efd47. Same problem.

Aren Cambre wrote:

Just updated to b1efd47. Same problem.

I can't see Nyall commit

https://github.com/qgis/Quantum-GIS/commits/master

so I would not expect to see any difference, yet.

No - it's in there (573efab5a87278d6795412cb3b4de65b5d259a3f) ... but it's not working for me either now. I'll have to look into it more.

Think I've finally sorted this one out - pull request #789 fixes it.

It's caused by the filter returning records with null geometry - bug #8192 meant qgis was incorrectly calculating the bounding box for the resultant layer, thus breaking the heatmap.

If a project was saved with the filter, then loading the project caused QGIS to calculate the extent using the provider, resulting in a correct bounding box -- this led me to believe the earlier fix was working, when in reality it was just because I was working from a project with the filter applied.