[GIS] ATLAS automation in QGIS showing data from multiple layers (based on attribute from one of the layers)

atlasqgis

I have a QGIS project with four layers: A, B, C and D.

I need to prepare an ATLAS automation based on layer A. On maps I want to see data from layers B, C and D (from A not necessarily) but the data needs to match to the attribute from table A selected for automation (the Coverage layer = Layer A, Filter with = values from 'Feature ID' column, Sort by = values from 'Feature ID')

Example:
Layer A – ATLAS automation based on values in attribute table from column: 'Feature ID' = 100, 101, 102 and so on.

Data from layers B, C, D visible on maps: features from layer B (C, D) where values in each attribute table from column 'Layer A Reference No' = 100, 101, 102 and so on.

I don't want to see the other features from layers B, C and D (where values are different than the ones selected for ATLAS automation (for example 87, 88 or 94)) for layer A – only the ones which match.

In the end I would see on the first map the data from layers B, C and D where attributes in the column 'Layer A Reference No' = 100 as this is the first map selected by ATLAS (based on Coverage layer A).

On the second map (where ATLAS selects value 101 from layer A) I would see only the data from layers B, C and D where attributes in the column 'Layer A Reference No' = 101.

Is this possible without Python?

At the moment the only thing I can do is to query layers B, C and D in order to see on the map the data where the value in the column 'Layer A Reference No' = 100 (for the first map), 101 (for the second map) etc. and then use layer A for setting location.

But I have to prepare 200 maps!

Best Answer

I have found the solution.

Atlas generation TAB

Layers B, C and D

They need to be rule based (style) and need to contain the following rules (in Style):

"Feature ID" = attribute( $atlasfeature , 'Feature ID') - for visible records

"Feature ID" <> attribute( $atlasfeature , 'Feature ID') - for all records we don't want to see ( I styled it as transparent)

.....................................................................................................................................................................

Settings for the layer A, which works with ATLAS:

Configuration section:

Coverage layer: A

Hidden coverage layer: - TICKED

Filter with - NOT TICKED - this is important as the automation won't work otherwise

Output section:

Output filename expression: attribute($currentfeature, 'Feature ID') - this is not mandatory but will produce single files with the name = to the values from Feature ID column

Single file export when possible - NOT TICKED - this can be ticked in order to create a booklet, but not in my case

Sort by: Feature ID

.....................................................................................................................................................................

Item properties TAB

Below are my settings for the Map in the Item properties panel

.....................................................................................................................................................................

Thanks Jesse again. I hope this will help the others as well at some point.

Regards, Maciek Drozda

Related Solutions

[GIS] QGIS Atlas: Filter maps based on attributes (more than one)

You need a polygon layer which will be your atlas coverage layer:
1. Since all the maps will have the same geographic boundaries just create a layer with a polygon that covers the whole area and make as many copies of that polygon as 'Party' + 'Year' combinations.
2. Add a party_year field that you will populate with the different combinations of Party and Year.
Now set your atlas with that layer as your coverage layer and use the field party_year to name the atlas pages. Remember to check the 'Hidden coverage layer' option as you don't want your coverage layer to show.
To shows the location of the representatives based on their Party + Year, render your point layer using a rule based style with this rule:
```
concat("Party","Year") = attribute(@atlas_feature, 'party_year')
```
Navigate though your atlas pages to see the result.

[GIS] Attribute data in QGIS Atlas

Summarized:

You can create a virtual_layer that combines every feature contained by a park. Or - when dealing with a lot of layers - it is preferrable to make use of a database, for example SpatiaLite where you create a view.
Then you add a relation park-virtual_layer/view.
In the print composer you can add a table and select as source: 'relation children'.

Only the 'linked' features will show up in the table.

In detail:

Suppose you have a polygon layer (parks), line layer and points layer.

Create a SpatiaLite database (How to save multiple layers from QGIS to a Spatialite db?) and load all your layers into it.

Make a view with the following code:

create or replace view parks_contains as

select a.id, a.in_park
from 

(
select parklayer.id, layer1.attributeA as in_park
from parklayer
join layer1 on st_intersects(parklayer.geometry, layer1.geometry)

union

select parklayer.id, layer2.attributeB as in_park
from parklayer
join layer2 on st_contains(parklayer.geometry, layer2.geometry)

union

select parklayer.id, layer3.attributeC as in_park
from parklayer
join layer3 on st_contains(parklayer.geometry, layer3.geometry)

union

etc...

) as a

where in_park is not null

You can union as many layers as you want. Just be aware to name all outputfields the same. How it works:

In the main codeblock you make a join between the parkslayer and each other layer. In the join you define how the other features will be 'linked' to each parkattribute, using a command like st_within() or st_intersects() (for more detail look at http://www.gaia-gis.it/spatialite-2.4.0-4/spatialite-sql-2.4-4.html#p12)

For each feature that lies in a park there will be a row in the resulting table :

Load that new table into QGIS and add a relation project > project properties

In the printcomposer you can add a map, set it to be controlled by atlas. Add a table and choose 'Relation children' as Source.

Best Answer

Related Solutions

[GIS] QGIS Atlas: Filter maps based on attributes (more than one)

[GIS] Attribute data in QGIS Atlas

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