7.3 Initiating a QGIS Project
Before creating a new GIS project, we need to explore the data that we will be analyzing. You will see that a folder of GIS data contains numerous data of various formats. For example, vector data on a particular object will at least have an .shp file (the main file containing the points, lines, and polygons), an .shx file (an index file), and a .dbf file (a database file containing attributes of the object). Thus, it is important that we organize our data properly to ensure an efficient work process.
Once you have a created a new project in QGIS, you can easily locate your data files by adding them to Favorites. To do this, right-click Favorites, click add a directory, and select the folder containing the data that you are working on.
There are 2 ways to add data to your project. You can click on the Data Source Manager (icon on the upper-left corner that looks like 3 stacked papers) and choose to import raster or vector data. You can also expand the folder that you have put in Favorites and drag the files to the display window.
Video: Start New Project in QGIS
The following video will describe the process of creating a new project, locating data, and saving the project within QGIS. This is a process that you will use every time you need to analyse new data within QGIS.
Sample data from the video:
7.3.2 Changing the Coordinate Reference System (CRS) in QGIS
When we are working with maps, we are essentially working with projections of the earth that transforms the earth’s spherical shape into a flat shape. A coordinate reference system (CRS) tells us how locations on a map projection relate to real locations on the earth’s surface and is therefore important for our spatial data analysis.
However, the data that we are working on might not contain information on the coordinate reference system that was used and so we would need to set the CRS manually. To set the CRS of a layer in QGIS, we would need to enter the EPSG code for our area of study which can be found on this website.
Video: Changing Coordinate Reference System
The following video will help you change the coordinate reference system within QGIS. Not only is it important to know how to do this to visualize your data correctly, it can also affect the accuracy of your analyses.
Sample data from the video:
For our dataset from Ecuador, we selected WGS 84 / UTM zone 17S (EPSG:32717)