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Analyzing Geographic Data with QGIS – Part 1

Today I’m writing this post to explain how it’s possible to make geographic analysis and answer questions like: which is the richest area in my city? How many people do live in one neighborhood? 

You can do it combining shape files with an excel spreadsheet, let’s understand it together…

First of all, we need to install one Geographic Information System (GIS), and I recommend QGIS – free and open source GIS

Then, we’re gonna need one shape file and one excel spreadsheet. I’m from Brazil, and we do have a lot of open data from States and Cities. In this post, We’re gonna use São Paulo Map (shape file) and economic data from the city (here).

Opening QGIS we can just drag and drop the shape file in the area marked by the red rectangle.

Analyzing Geographic Data with QGIS – Part 1

When we drop the shape file, Qgis’ll load the file and ask about the Geographic Coordinate System (GCS) , as we can see in the example bellow:

Analyzing Geographic Data with QGIS – Part 1

In this case, we’ll choose SAD69/UTM 23 because I know the GCS used to create this shape file. We must know it in advance, if we don’t have any idea and we choose a wrong GCS, our shape file’ll be in an incorrect geographical position. After choosing the GCS, QGIS’ll load the shape file and present it to us.

Analyzing Geographic Data with QGIS – Part 1

Now, we need to load the excel file. In this example, we’re gonna use economic data (population, employees, average salary and so on). To load an excel file, we can drag and drop as we did with shape file. QGIS’ll ask which spreadsheet we want to load, we’ll choose this one selected below:

Analyzing Geographic Data with QGIS – Part 1Now, we need to link the shape file with excel file. We can do this making a double click in the shape file on the left (SAD69-96 SHP…). The window bellows will open, click on Union and then + . After that, on union field, select Field3, on field target select ds_codigo, click on ok and ok again.

Analyzing Geographic Data with QGIS – Part 1

Now we have all the excel data linked with shape file, as we can see:

Analyzing Geographic Data with QGIS – Part 1

We’ll discuss more about geoanalysis in next post. If something is not clear, write a comment for me please.

Whether you like, click on it or write a comment too.

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