cmhh

Rendering Markdown on the Web using zero-md

This post demonstrates the use of zero-md to render an external markdown file in a web page, and populate a navigation element.

Building a New Zealand Address Geocoder (1)

Building an Address Parser

This post outlines a method for parsing address strings using a bidirectional long short-term memory network.

Building a New Zealand Address Geocoder (2)

Building a Geocoding Service

In this post we create an address geocoder using an address parser and a database of addresses.

Guitar Chord Transitions with Vue.js

A basic Vue.js component for rendering guitar chord diagrams, and for animating chord transitions.

Azure Functions with Scala using the Java Handler

In this post we look at how we create an Azure Function in Scala by making small changes to a basic Java function.

Azure Functions with Scala using a Custom Handler

In this post we look at how we can write an Azure Function in any language. We do this by creating a simple web service in our language of choice (Scala), and then using it as a custom handler from a host Azure Function.

Loading Spatial Data to Snowflake from R

Loading spatial data to Snowflake can be a little awkward. Here we describe a simple and performant approach using the ODBC or JDBC drivers from R.

Deploying Shiny Applications

There are many ways we can deploy Shiny applications for external consumption. This post describes several possible methods.

Serving PostGIS Features Over HTTP

Does it bother you when you’re forced to fetch features via an API, instead of just downloading a file from a file server? Same! As a solution of sorts, I wondered how easily we could make a service which could be used to download features directly in a requested format.

Too Much Shiny?!

Shiny provides a low-entry option for R programmers to develop single-page web applications. But, in my opinion, it is over-used. In this post we consider where Shiny might be a good option, and where it might not.

Agent Based Simulations with Akka

In this post we attempt to approximate a household survey collection as an agent-based simulation. The simulation designed using the actor model, and implemented in Scala using Akka.

Data Services from Existing PostgreSQL Databases

Sometimes creating a bespoke data service is easy enough. But maybe sometimes it’s just easier to expose data that already exists in a database. Here we consider a couple of options, PostGraphile and PostGREST, for doing just that.

Online Learning with Akka

Imagine an online learning scenario where we wish to update an existing model using streaming event data, say. Here we consider how we might approach such a problem using the actor model as implemented by Akka.

Online Learning with Apache Kafka

Imagine an online learning scenario where we wish to update an existing model using streaming event data, say. Here we consider how we might approach such a problem using Apache Kafka.

A Brief Look at Apache Sedona

Apache Sedona, formerly GeoSpark, is a library that let’s us make spatial RDDs and DataFrames in Apache Spark, as well as to run spatial queries. Feature classes can get…

Working Productively on Windows Using Windows Subsystem for Linux 2 and Docker

A relatively common scenario in enterprise is to provide users a Windows desktop with a relatively small set of tools, and without administrative access. Depending on the…

Docker on Windows with Windows Subsystem for Linux 2

Windows Subsystem for Linux version 2 (WSL2) brings something like a native Linux environment to Windows. And because it’s native, we can even run Docker on WSL2 and access…

Using PostGIS as a Spatial Backend for R

Here we look at how we can leverage PostgreSQL and the PostGIS extension to usefully complement R, mostly by offloading large geoprocessing tasks, and as a library for storing large feature classes for shared use across a potentially large userbase.

Seasonal Adjustment as a Service

X13-ARIMA-SEATS is a widely used seasonal adjustment program developed by the U.S. Census Bureau. Here we look at how one might go wrapping this program as a web service for remote execution.

Building Tile Services on-the-fly with GeoServer

Sending large vector features over-the-wire for use in slippy maps is bad, m’kay. One possible solution is to appeal to a tile service or similar, and here we look at how we might leverage the GeoServer API to enable end-users to quickly deploy their own tile sets on-the-fly.

Web Maps and Tiles with QGIS

In this post we look at how we can use QGIS Server to publish a range of services using WMS, WFS and WCS.

Serving Geospatial Features with Mapnik and TileStache

When making maps for display on the web, the size of the various objects being rendered can quickly become overwhelming. One solution is to appeal to a tile service, and here we consider one approach using Mapnik and TileStache.

Routing in R Using the Open Source Routing Machine (OSRM)

I often find myself needing to establish the travel time or distance between arrays of addresses from R. Here we describe how we can use a local install of Open Source Routing Machine as a solution which is highly performant, and relatively easy to implement.