QGIS 2.10, csv points to vector grid

Question

I have a series of point data from a .csv file that I would like to display as a heatmap raster, the .csv data have various attributes with them and I would like to adjust the color ramp based on which of those attributes I select. My first thought was to apply a color ramp to a vector grid based on how many points are in the grid cells.

However, I'm a beginner at both GIS and this is my first time using QGIS. I'm happy to thrash around on my own. I've tried to create a vector grid, but pretty sure I've done it wrong because although a layer was added to the TOC I saw nothing on the canvas.

Answer 1

For a quick 'heat map' view of your data:

Use the Layer > Add Layer > Add Delimited Text layer menu option from QGIS

Browse to your CSV file, and ensure your X and Y fields are being used properly:

Click OK and you'll be asked what coordinate system to use. Assuming you're using LAT/LON in WGS84, choose EPSG:4326, then click OK and your points should be added to the map:

Now double-click the layer you just created, choose the Style option, then from the pull-down in the top-left, choose Heatmap, and then Apply, and you should see your points rendered as a heat map:

Play around with those settings to get something you like!

In order to use the attributes you've mentioned, simply adjust the layer settings, query defining the features you're viewing, etc.

Otherwise, I can never get the 'heatmap' tool to work...

Answer 2

Things to check:

1. Is the map set to the coordinate system used in the CSV, and/or was the coordinate system set in the new layer?
2. If you right click the layer in the TOC and click Zoom to Layer, do the points appear? If so, are they in the right area?
3. If not, something to check is did you define the X and Y coordinates properly, or did you flip them? It's an easy mistake to make.