Open Source GIS: Enterprise GIS w/ Postgres/PostGIS

In this lecture, you will learn what an Enterprise GIS is, the stages in enterprise GIS implementation , and the example scenario used in this course.

In this lecture you will learn how to download and install PostGRES, PostGIS, and QGIS. While many courses have the software waiting for the students to use in order to simplify things, we will actually show you how to install PostGRES, PostGIS, QGIS, and other extensions to make the enterprise GIS work.

In this lecture you'll download QGIS and install it on your local computer. The current directory for downloading QGIS is located at https://qgis.org/en/site/forusers/download.html

Simply follow the video to download the software, and remember - QGIS is big! This is going to take some time to complete.

In this lecture you will actually load a variety of data (attribute and spatial) into PostGRES and PostGIS. Particular attention will be paid to open source tools available for data loading, and also how to manage different coordinate systems in the database. Unlike many courses that already have the data waiting for you, this course will make sure that you know how to load the data yourself!

In the last lecture, we simply imported our data using a backup file. But, there are many ways to get spatial and attribute data into Postgres.  This lecture will look at about 5 different ways to get data into Postgres, and all the different options you have at your disposal.

If you've ever used a multi-user enterprise system, you may have wondered how some users have access to certain data but not other data. In this lecture, you will learn how to create specific working GROUPS, and assign those groups to individual layers. You will create groups that have full control over data, view only capabilities, and limited editing capabilities. In the next lecture, students will create individual login roles for specific users who will inherit the permissions granted to the groups.

In this lecture, you will learn how to create VIEWS to control what a user might see in the database. Rather than having a user directly link to a layer, a VIEW will allow the database manager to create a visualization of the data that an end user can see. In this lecture, we will focus on creating a specialized view from a simple attribute query, a more complex query that spans multiple tables, and a spatial query that re-imagines the original layer to take on the characteristics of the spatial query.

One of the things that makes an enterprise system so powerful is that you can create constraints that protect your data from erroneous data entry. Many GIS implementations have a middle-ware tier to handle data integrity. But, it is often easy to bypass these securities. In a real enterprise system, all the logic and security is handled by the database itself - in other words, you can't circumvent the security. In this lecture, you will learn how to add constraints to the data to ensure that data is properly protected. And unlike many of your GIS counterparts, you can state that the data is protected no matter what system a third party uses to access the data.

In this lecture, you will learn how to create triggers, that will fire off in response to some action the user might take. Specifically, you will create a trigger that automatically updates a value in the parcels table with the watershed it is contained in. Also, your trigger is going to make sure that the new geometry you create actually falls inside a watershed boundary. This is a really powerful way to control your data quality and also automatically perform analytical tasks in response to a data editing activity you might perform.

While the work we did earlier demonstrated some really cool features of constraints and triggers, it is going to be cumbersome to add data for the remainder of this training.  So, this lecture is going to modify the functions and triggers so that we can more easily digitize the data. Make sure to run this code, so that you'll be able to add data for the remainder of this training.