Copying Rasters in PostGIS

I ran into a process where I wanted to create copies of rasters in PostgreSQL. While seemingly a simple process this took me a bit of work to figure out.

For my workflow I had three rasters, which all have the same size, and I want to load them into the same PostGIS table with three raster geometry columns. I don’t think this will work for different sized rasters since the rid’s will not match.

Three rasters:
raster1
raster2
raster3

Which I want to copy into:
merged_raster

First to create the merged raster table:

Then to add the rid’s. These are the id’s of the tiles that the raster was split into when loading. If your tile size is large enough then you may only have one.

Then copying the actual data is straighforward (this assumes the raster column in the raster1 datasets is called rast):

Now I still have an issue that QGIS will not load these layers. It will always load the initial raster column no matter what is chosen.

Anaconda install with OSGeo4W

I was coming across some errors when installing Anaconda, Miniconda specifically.

https://conda.io/miniconda.html

I think part of the reason is I have quite a few installs of Python due to OSGeo4W.

My error:

The solution:

Update the activate.bat file that is called when launching from the start menu. For me located in:

We need to add in the following to clear out and reset the python environment before launching anaconda:

So, editing the file from:

To:

Updating the paths as required.

This just clears out the python and windows environmental variables before launching, similar to what OSGeo4W does.

Ireland and Dublin Street Orientations

Based on the work by:

Geoff Boeing: Comparing City Street Orientations

Rixx: Street Orientations

The graphs show the percentage of streets that run in a certain orientation. So for a grid based city like Chicago, there will be a heavy bias in north/south and east/west streets. Bearing in mind north and south will be the same (unless there are one-way streets, which only count in the direction they run in).

But for older cities that formed naturally, without modern city planning, the streets should be more varied.

Ireland:

Largest populated places by population. Based on the Ordnance Survey Ireland urban areas. As it is OSI data, Northern Ireland is not included.

Dublin Postcodes:

Some areas are clearly impacted by large motorways running through them.

And for non-Dubliners, a map of the postal district boundaries:

I updated the script by Rixx, so that it would take a ShapeFile as an input with a few caveats (it must be WGS84, it must have an attribute that has the are name and it must be called settl_name).

Check out the script at: GitHub

Stanley Cup Champions Since 1915

Stanley Cup Champions Since 1915:

Average Location of Stanley Cup Champions Since 1915:

The average locations were created using a window function in PostgreSQL. We can utilise the geography type to take into account the curvature of the earth and make the calculation on a spheroid.

So for the average location of the last five years: