Overview
Grids for Atlas plugin (in French "Synoptiques pour l'atlas") allows you to create a vector layer grid for an atlas, in an automatid way.
It uses a coverage layer's geometries which contains the area to cartography. This layer will define the grid extent.
It also uses a composer to define the dimensions of a single ladder into the grid.
Ladder attribute ids are generated for the grid to be used as inputs for the Atlas plugin and define the atlas sheets numbers.
You will be able to create two differents types of grids : the classic grid which is particularly adapted to non-linear polygonal coverage layers, or the dynamic grid, more adapted to linear shapes.
Create a QGis project
You first have to create a QGis project containing a vector coverage layer for your grid
Create a composer
Then you create a composer, containing a map object which will define the grid ladder's dimensions.
Procedure :
- Zoom in the project map window to the scale you want as reference for the grid ladder dimensions.
- Create a new composer and insert a map object.
- Adapt the map object as you want, and fix for one moment your mouse coursor on it. A tooltip appears that gives you the name of map object to remember (Map 0 for example).
Grids for Atlas plugin
You're now ready to launch the plugin. Find the menu entry and click on the Synoptiques Atlas or Grids for Atlas button. The following window should appear.
You have to fill in the form before clicking on Create grid(s) to launch the grid generation. Here are the different options :
- Generate classic grid
- Generate a classic grid covering the entire coverage layer.
- Generate dynamic grid
- Generate a dynamic synoptic, particularly adapted for linear-shaped coverage layers.
- Coverage layer
- Choose the (vector) coverage layer, that corresponds to the extent you want to cover with the grid.
- Composer
- Select the composer which contains the map object with the extent that defines the grid ladder dimensions.
- Refresh composers list
- If you have created a new composer, this will permit you to refresh the composers list.
- Show
- Show the composer window corresponding to the selected element in the list.
- Composer map object
- Choose the reference map object into the composer (you can check the name in the composer window, fixing for one moment the cursor on it).
- Output directory
- Select the outfiles directory where grid (or synoptiques) shapefiles will be written, using the "Browse" button. Warning : if a grid has already been generated, please delete the corresponding layers in the QGis project before launching the Grid tool again!
- Create grid(s)
- The "Create grid(s)" button lauches the grid(s) generation, and writes the outputs in the chosen directory.
Results examples
The results are written in the specified directory and displayed in the map window.
Result example for a non-linear coverage layer with classic grid :
And result example for a linear coverage layer with dynamic grid :
Possible corrections to add
It may be micro-areas of the coverage layer still not covered by the grid. In that case, you will need to move by hand in an editing session the concerned ladders.