IDEAtlas

The project adopts a user-centred approach where various local, national and international stakeholders have participated in the co-design and co-development of the AI-based solutions. The project builds on previous and partners with ongoing works and available data generated within IDEAMAPS and SLUMAP. The project team utilizes an extensive network to identify and engage with Early Adopters (in the pilot cities) and stakeholders (e.g., IDEAMAPS, GEO, and GEO-HPI) for the collaborative development.

The developed algorithms have been implemented and integrated into a cloud-based end-to-end processing system, and its performance demonstrated in eight test cities spread around the globe, demonstrated in the figure below. 

Available data

 IDEAtlas provides now the preliminary results of the informal settlements mapping for each of the 8 cities mapped, as well as the reference maps used to train the AI algorithms. Besides that, the IDEAtlas portal contains all the urban areas produced by the Global Human Settlements Layer, with the possibility of entering new data related to any of the cities in the world. This data will be then stored in our GeoServer and accessible through the portal.  

Data portal

 In order to enable a fast interaction with IDEATlas local co-anchors and local stakeholders, we developed a data portal where we they can visualize the most recent results produced by our project and provide feedback in an efficient way. This portal is being also improved to be the main point of dissemination of the results of the project and, in the future, will also serve for the development of benchmark datasets of informal settlements mapping.  

Slum Severity 

The slum severity can be generated according to the IDEAMAP Domain of Deprivation Framework (Abascal et al. 2022), informed by the main characteristics of settlements (https://www.sciencedirect.com/science/article/pii/S019897152200014X). For this purpose, the EO boundary of settlements can be combined with ancillary data. 

• • Integration of local data layers (e.g., on access to services & infrastructure, hazards, open and green spaces, access to public transport) with the gridded settlement extends (100m grid cells) to assess variations in living conditions. The target year will be 2023/24 to have the most recent layer. At the extent of the administrative city (depending on data availabilities.) 
  • Aggregated for the settlement boundary (polygons) and overall assessment of the degree of deprivation (e.g., from 0 meaning least to 1 meaning most deprived). Furthermore, the development of local typologies of slums. 

Portal and Software 

After analyzing the layer of informal areas in the IDEAtlas data portal (https://portal.ideatlas.eu/), the next step will be to use either the gridded or polygon layers to understand the diversity of settlement. To understand diversity of settlements that relate to upgrading needs or economic opportunities for development, we use a slum severity model. To develop a slum severity index that will support local policy making (e.g., strategic investments) it is important to understand local conditions and local upgrading (improvement) needs. We suggest to use a GIS based model to calculate the slum severity index. The modeling can be done in any GIS software package (e.g., QGIS a free and open software). 

QGIS is a geographic information system (GIS) software that is free and open-source. The software can be freely downloaded. We recommend to use the current Long Term Release (LTR) QGIS. After installing the software you will be able to add data that are relevant (see table above) to calculate the slum severity index. 

 Saving a QGIS project

The state of your QGIS session is called a project, and this state can be saved into a QGIS project file. This means you can close a project and open it up again to continue from where you left off. Any

operations to do with saving, opening, or creating a new project can be found via MENU Project. A project file is saved in QGZ format (i.e. a .qgz extension).

The project file saves a lot of information about the status of the project, including the layers added, their properties (e.g. symbology) etc. but it is important to note that the data itself is not saved in the project file - only the relative path to the data source.

This means that it is important not to change the location of the data relative to the location of the project file (i.e. to not move the data to different folders once the data has been added to QGIS, as QGIS will no longer be able to find it).

Another example, when sharing a QGIS project with others, you must also share the data which is used in the project (keeping the same path logic between the project and the data).

Save the QGIS project

Save the project as a .qgz file in the folder that contains the material for Lesson 2 (MENU Project ►

Save As…) e.g. (…\Lesson_2\Lesson2.qgz). It is important to save your work regularly!

There are many different formats in which vector data can be stored. The most well-known is the ESRI Shapefile (extension .shp), but others such as .kml and .geojson are also commonly used. All data formats compatible with GDAL/OGR are also compatible with QGIS (https://gdal.org/drivers/vector/index.html ).

The new standard format is now the Geopackage (extension .gpkg). This format has the advantage that it allows the storage of multiple GIS data (layers) in a single file. Unlike the ESRI Shapefile format, a single GeoPackage file can contain various data (both raster and vector), in different coordinate reference systems, as well as tables without spatial information and layer style files, amongst other advantages. These features allow you to share data easily and avoid file duplication. For more information on the GeoPackage: https://www.geopackage.org/

Adding  data to QGIS

There are a number of methods that can be used to add data into QGIS, and many different data types.

Via the Browser panel

In the QGIS Browser panel, navigate to the folder containing the data for this lesson. You can also directly access the data from the folder added to the Favorites earlier.

Calculating a slum severity index

There are many option to combine different data sets (e.g., built-up density and accessibility) into an index.  One option is the Raster Calculator in the Raster menu. It allows you to perform calculations on the basis of existing raster pixel values. The results are written to a new raster layer. Before performing such a calculation the input layers need to be normalized (with values ranging from 0 to 1 - normally 0 refers to no deprivation and 1 to very high deprivation). 

Visualising data layers

In the Layers panel, is a list of the layers present in the project. The check box shows whether the layer is visible or not. The symbols at the beginning of each layer name, indicate which type of vector is present (point, line or polygon) and the symbology of the layer. 

The order of the layers in the Layers list controls the order in which they are displayed in the Map view. The priority of visualization follows a top to bottom rule, which means that the top layer overlays the others. You can change the order of the different layers, or visualize various layer combinations by ticking and un-ticking layers.

Attribute table

An important characteristic of vector data is that in addition to their geometry, they have an attribute table, that describe the elements in a vector file. Attributes can be used, for example, to symbolise elements (e.g. colour and style), create labels, to quickly search for specific elements, or to spatially analyse vector data.

To open a vector attribute table, you must first select the layer in the layers list. You will know that a layer is selected when it is highlighted (in blue or grey). You can then either

• Click on the attribute table icon (in the attribute toolbar)
• Select layer ► Right click ► Open attribute table

 What makes a good map?

The aim of a map is to communicate information. Often, maps are created to present information to people that do not have a background in GIS. The process of making a map, therefore, is the process of arranging the elements of a map in a way that, with very few words, any person can understand what the map is about.

There are certain elements that are necessary when producing a map.

• Title – with the theme, and can include the location of the map if this is useful
• Map body – The most important part of the layout, as it contains the map information. It should be as big as possible
• Legend – this explains all the symbols on the map, e. how to understand the data in the map. It should be complete, clear and easy to understand
• Scale-bar – represents the ratio of a distance on the map to the actual distance in the real world. It is necessary to understand the area covered by the map, and is especially useful when changing the size of the map.

·       North arrow

• Sources of the data used to make the map, and their date

Other optional elements can be added to a map, e.g. a graticule, an overview, the projection system, the software used, author, logo … etc. Together, these elements help the map reader to interpret the information shown on the map.

Map layout in QGIS

In QGIS, the Print layout is used to prepare maps for printing or exporting to documents. The Layout manager is used to manage your print layouts (you can make more than one). You can access the Layout manager via

·       MENU Project ► Layout Manager

• Or in the Project toolbar ►

Within the Layout manager you can, as the name suggests, manage your layouts. Each layout must have a unique name. If you have at least one layout in the project, these buttons will become available. These can be very useful, e.g. if you would like to make a second map only slightly different to the first, the Duplicate option can be very useful.

Click on Create and on the window that pops up (Create Print Layout), give a useful name to the map