Category: QGIS

Creating maps in QGIS: Where to start?

Now that you have QGIS 3.4 installed and running, what do you do next? In this post I will show you where to get your GIS (geographic information system) data, and how to open them in QGIS.

1. Download GIS files. We’ll start off easy—we need to download GIS shapefiles from Natural Earth. If shapefile is a foreign word for you, don’t panic! A shapefile is basically a geospatial vector data format that GIS software can read. A shapefile is made up of atleast three different files and you will notice it when you unzip your downloads; .shp, .dbf and .shx. This post from GIS Lounge explains it well.

Natural Earth website screenshot
You can download all the cultural files in one go (link on top of the page) or you can start with these layers:
Admin 0- Countries
Admin 0- Boundary Lines
Admin 0 – Breakaway, Disputed Areas
Admin 1 – States, Provinces

Optional layers from the Physical Vectors page:
Coastline
Ocean

After unzipping the files, I placed them in one folder for easy access.


2. Drag and drop all the .shp layers to QGIS. I will start with two layers, so it won’t be two overwhelming. Here I have the countries shapefile, and the disputed areas shapefile. You can see your layers on the Layers Panel on the left side of the screen.

The next step is to learn how to style the layers (unless you want to keep your map purple—or whatever color QGIS picked for you)  and to familiarize yourself with the Layer Properties window, or the Layer Styling column. We can explore that in the next post.

-Hx

QGIS Sorceress in Training: A QGIS User’s Story

Presented during FOSS4G SoTM Oceania, November 21, 2018.
@hannahdormido | [email protected]

Here is the video of the presentation:

 

Who am I?

I am Hannah, and I see myself as a full-time journalist, part-time mermaid, and a QGIS sorceress in training. I am a journalist by training and profession, but learned mapping using QGIS as I specialized on data visualization.

Why am I a sorceress in training?
Sorceress: Because when I first encountered QGIS and all that came with it, I asked myself “what kind of sorcery is this?”
In training: Because every single time I feel like I’ve mastered QGIS, something new comes along, or someone else does something cool that of course I want to learn how to do. So never a master, always in training! Don’t you fret, it is a good thing!

 

This was me doing a freelance gig a while back—way before my GIS days. Those were the days when I had no clue what a shapefile was, or what a kml was for.

How did I learn QGIS?

  1. I learned QGIS via Youtube tutorials created by my former Graphics mentor.

2. I followed GIS people on social media and joined groups. Even though I am based in Hong Kong. QGIS Australia has kindly adopted me into their community. You can find us on Twitter and check out the website. You can also join The Spatial Community on Slack. There is a channel for #QGIS, among other spatial-related topics.

3. I read a lot of blogs, like Anita Graser’s Free and Open Source GIS Ramblings. I also bought and read books on QGIS, mapping and data visualization.

What I’ve created using QGIS?

 

Choking on Our Harvest
(Can’t take all the credit for these three gorgeous maps, I had design help from my colleague Adrian Leung in Hong Kong).

Pollution Maps

If you are someone who wants to learn more about QGIS but don’t know where or how to start, please feel free to message me. I would be more than happy to share what I know, and help however I can. QGIS and mapping might appear intimidating at first, but you are not alone in learning—there’s a huge QGIS and open source GIS community that have your back: all you have to do is reach out!

Thanks,
Hannah
@hannahdormido
[email protected]

How to create a choropleth map in QGIS

1. Format your data. Create a csv and csvt. Save with the same file names, same location (ie. test.csv and test.csvt).

2. Bring your datafile to QGIS. Drag and drop works.

3. Merge your files. Double click on your base layer (.shp file). The Layer Properties window will open. Go to Joins.


Click on the green + button at the bottom of the window. A pop-up box will appear. Choose the layers you want to join, and the fields you want to be merged. The Join field and Target field should have have similar data so they can be merged. For my dataset, I used country names as the point of merger. Hit OK.

4. Create an editable layer of your merged layers. To do this, right click on your .shp file, choose Save As, then go ahead and create your ESRI file.

5. Colorize your map. Open Layer Properties of new layer. Go to Style, click on the dropdown (default is usually Single symbol) and choose Graduated.

6. Customize. Choose which data column you want to use, toggle methods between Color and Size. For this we want to use Color. Choose the Color ramp you prefer. If you click on the dropdown menu, there should more colors to choose from. 

7. To classify your data, choose the mode you want to use. I used Pretty Breaks for this one, and 5 classes. Then click Classify and it will show you the symbol and values. Hit apply, and this will show on your map. Other mode of classification are Equal Interval, Quantile, Standard Deviation, Natural Breaks.


Note: The countries with values are not colored accordingly, I added an underlying layer for the other countries that don’t have values.


8. If you want an SVG of your map, go to Project > Print Composer, or simply Command + P.  To print the map, click on the button that looks like a  blank canvas with green + button (left hand side, sixth icon from from the top). To save as SVG, click on the icon which looks like a canvas with a snowflake. If you want to print the key/legend, click on the icon with colorful boxes, third icon down from Print.



Here’s how to use the print composer:

Let me know if you have questions! 
Hx