How to use the Atlas function in QGIS?

How to use the Atlas function in QGIS?

This post explains how to use the Atlas function in QGIS to automate the production of maps from a single layer in order to produce a map output for each column in an attribute table.

How to get attribute values of another layer with QGIS?

What is clear: When using QGIS expressions on a layer, it is possible to relate to features of another layer with get_feature (layer,attribute,value) (enter the value and get the first feature with this value) or get_feature_by_id (layer,feature_id) (you enter th id of the feature you want to get). Adding geometry (feature) gets the geometry.

Is there a way to map by field in QGIS?

The normal way would be to set the coverage layer to be some kind of geographic layer and then QGIS would iterate through it spatially, but this is a kind of non-spatial solution that allows us to map by column instead.

How to automate the print layout in QGIS?

Switch back to the main QGIS window and right-click the HI_Wetlands_Poly layer and select Properties. In the Symbology tab, click on Simple fill and select Shapeburst fill as the Symbol layer type. Choose the Two color option and select shades of green and blue that you like.

How to generate table with unique values in QGIS?

QGIS now has a tool that will list unique values in one or more fields in a layer. “This algorithm generates a report with information about the unique values found in a given attribute (or attributes) of a vector layer.” Can be found in main menu Vector> Analysis Tools> List Unique Values. Generates a table with unique values.

How to run SQL statement in QGIS 1.8?

I am using QGIS 1.8. Since QGIS 2.14, you can use run SQL statements on any loaded vector layer using Virtual layers. In the Create virtual layer dialog, enter you SQL statement in the Query field. Something like: Click Ok and a table will load in QGIS with the desired unique values.

Where do I find the expression tab in QGIS?

The Expression tab provides the main interface to write expressions using functions, layer’s fields and values. It contains widgets to: type expressions using functions and/or fields. At the bottom of the dialog, is displayed the result of the expression evaluated on the first feature of the layer.

What are the types of expressions in QGIS?

This group contains operators (e.g., +, -, *). This group contains functions to handle conditional checks in expressions. This group contains math functions (e.g., square root, sin and cos). This group contains functions to convert one data type to another (e.g., string to integer, integer to string).

How to set an internal ID in QGIS?

You can select an attribute of the coverage layer or set an expression. If this option is empty, QGIS will use an internal ID, according to the filter and/or the sort order applied to the layer. An optional Filter with text area that allows you to specify an expression for filtering features from the coverage layer.

How to enable atlas generation on a map?

To enable atlas generation for a specific map item, you need to check Controlled by Atlas under the item properties of the map item. Once checked, you can set: A radiobutton Margin around feature that allows you to select the amount of space added around each geometry within the allocated map.

How to export an atlas with a python script?

– Geographic Information Systems Stack Exchange Export a configured Atlas with a Python script / command line?

What is the definition of Eval in QGIS?

Well, it’s basically this, as described in the QGIS documentation: ‘eval’ – Evaluates an expression which is passed in a string. Useful to expand dynamic parameters passed as context variables or fields.