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When you work with databases, it comes often when you want to remove duplicates in your data. In this tutorial, we will see how to remove duplicates by selecting the highest value.

Introduction

Let’s say that we have a list of customers in a shop, and we want to have the highest price that each customer paid. Before we start let’s explore the data:


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In this tutorial we are gonna explore how to create a contained environment that can work on any operating system with the help of Docker.

Docker is a contained environment that makes it possible for an app to be run on different operating system. It has multiple advantages like taking away the pain of managing version conflicts or server configuration by using Container.

With a Container, the app is portable and can move from one operating system to another easily because of all the necessary dependencies and configuration inside of it. …


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In this last part, we will see how Nodejs/Express, Leaflet js and PostgreSQL all combined can create complete and powerful geographic applications that can be used in different fields ranging from environmental to cadastral domains.

Nodejs/Express

I think that most of the developers out there know what Nodejs is, so I will just say that with Nodejs, we can use one language (JavaScript) on the front-end and on the back-end. After installing Nodejs and express, we can add this dependencies in the package.json folder:

As you can see, we have just five dependencies. Let’s start with ‘dotenv’. It allows the…


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This article will show the guidelines on how to set up a PostgreSQL database with the PostGIS extension. The database created will let the user add a point, a line or a polygon geometry into the database.

To be able to follow this tutorial, all you have to do is installing PostgreSQL and pgAdmin4 on your computer. Don’t worry it’s completely free. You can find it on this link and it’s available for windows, mac and Linux users: https://www.postgresql.org/download/

Don’t forget to install the PostGIS bundle during the installation of PostgreSQL.

PostgreSQL with PostGIS

I think that everybody agree that PostgreSQL is a…


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This article will show the guidelines that makes it possible to create a web app with PostgreSQL database and her spatial extension PostGIS all that combined with Nodejs/Express for the back-end and Leaflet js on the front-end. I know it’s a lot of technologies altogether but I will try to make it simpler for you. This is the part one that will focus on the front-end.

Leaflet

Leaflet js is a mapping library that is used in JavaScript to manipulate maps on the web. The reason of the popularity of this library lay on the simplicity and clarity of her Docs…

Tarek BAGAA

Geospatial Developer | Bachelor Degree in Geographical Information Systems (GIS) Applied to Environment | I love to share solution that Geospatial has to offer

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