Data table

The data table is a central element of the Magrit interface. It allows the user to visualize and modify the data of each layer.

Data table

Data modification

To modify data, double-click on a cell and enter the desired value.

Data export to CSV

You can export the data table displayed in CSV format by clicking on the "Export to CSV..." button at the bottom left of the table. With this type of export, entity geometry is not exported (if you require an export type that includes geometry, you can use the "Export" function in the left-hand menu).

Adding a new field

You can add a new field by clicking on the “New column...” button at the bottom left of the table.

This feature is comparable to the “field calculator” functionality of GIS software such as QGIS.

Data table - New column

The current fields of the layer are accessible as shortcuts (yellow buttons) as well as three special fields (green buttons):

• $count: the number of entities in the layer,
• $id: the unique (and internal) identifier of the entity,
• $area: the area of the entity (if it is a polygon).

Several operations are possible (some are present as a shortcut - blue buttons):

• basic mathematical operators (+, -, *, /),
• mathematical functions (sqrt, exp, abs, round, floor, ceil and power),
• string functions (concat, substring, lower, upper, trim and replace),
• comparison operators (LIKE, =, !=, >, >=, < and <=), negation (NOT) and logical operations (AND, OR),
• condition construction (CASE WHEN ... THEN ... ELSE ... END).

In order to create a new column, it is mandatory to specify the name of the column to be created, the data type (stock, ratio, etc.) and the calculation formula. When the formula is valid, a preview of the calculated values (first 8 lines of the table) is displayed.

Data table - New column with valid formula

When the formula is invalid, an error message is displayed and the preview is not displayed.

Data table - New column with invalid formula

Data table - New column with invalid formula

Example of formula

Reclassifying quantitative data into qualitative data

Construction of formulas using conditional statements allows you to reclassify quantitative data into qualitative data. For example, to crate a new column "Type of population" based on the "Population" column with the following classes:

• "Small" for populations less than 1000 inhabitants,
• "Medium" for populations between 1000 and 10000 inhabitants,
• "Large" for populations greater than 10000 inhabitants.

CASE WHEN Population < 1000 THEN 'Small'
     WHEN Population >= 1000 AND Population <= 10000 THEN 'Medium'
     ELSE 'Large'
END

Extracting the departmental code from the INSEE code

To extract the departmental code from the INSEE code, you can use the substring function to extract the first two characters of the INSEE code.

substring(INSEE, 1, 2)

Calculating the population density of a territory

To calculate the population density of a territory, you can use the following formula:

Population / Area

Let's say that the area is in m² and you want to get a density in hab/km²:

Population / Area * 1000000

Deleting a field

To delete a field, right-click on the field name and select "Delete column".

Closing the data table

When you close the data table, a dialog box will appear asking you to save the changes made to the data. It's possible to save the changes by clicking on the "Confirm" button or to cancel the changes by clicking on the "Cancel" button.