GeoJSON

This article is a stub.

What is GeoJSON

GeoJson is a file format, which is meant to store data about geographical features (GIS data). It is a simple text-based format which can be inspected by humans, but is also readable by most GIS software.

How GeoJSON relates to the Tygron Engine

Projects in the Tygron Engine consist of a number of spatial data layers, such as constructions, zones, and land. When a project is newly created using the wizard, much of this data is already aggregated from available data. However, it may be desirable to load additional data into the project. The Tygron Engine can read GeoJSON files for this purpose.

When to use GeoJSON files

The Tygron Engine creates projects using the wizard with a number of default data sources. However, some users or organisations may have data which is preferable or complementary to the data already present in the project. This may be for a number of reasons:

• The project takes place in a location for which there are no data sources connected by default
• The default data sources are not accurate or up-to-date enough
• The project's intended starting situation is not the same as the real, current situation
• There is some form of data which is not covered by the Tygron Engine by default

In these situations, data in the Tygron Engine can be overwritten or supplemented by the user.

Data in the Engine

When loading a GeoJSON file, it can take the form of a number of data types. Currently, it is possible to use GeoJSON files to automatically create or update a number of types of data in the world. Data can be loaded in as:

• Constructions (Constructions placed based on the shapes defined in the file)
• Areas (Areas placed based on the shapes defined in the file)
• Zoning (Zones placed based on the shapes defined in the file)
• Construction values (Constructions are modified based on the attributes in the file)

How to prepare a GIS file

A GIS file can be converted into a GeoJSON file, so that it can be loaded by the Tygron Engine. Any GeoJSON file must conform to a number of prerequisites before it can be loaded properly. Files which do not conform to these prerequisites may not be loaded properly by the Tygron Engine.

• The file must be saved in GeoJSON format.
• The file must use coordinate system EPSG:3857, Pseudo Mercator.
• The file must use character encoding UTF-8.
• All desired shapes must be polygons. Not lines or points. Non-polygon shapes are ignored.
• All desired attributes must be numerical, so that they can be loaded as valid attribute values. Non-numeric attributes are ignored when attempting to load them as attributes.

To convert a GIS file so that it meets these requirements, almost any GIS application can be used. ArcGIS Desktop is one example. An open-source alternative is QGIS. Whichever application is selected should allow for inspecting the existing shapes, and transforming them into polygons. This can often be done by, for example, creating a buffer around any shape which is not yet a polygon. They should also allow for inspecting and adding attributes to the shapes. Any attribute information which is to be uploaded should be numerical. If any attribute is not numerical, the values of that attribute must either be changed to be valid numbers, or a new attribute must be created with a numerical value based on the desired attribute. When this is done for all desired shapes and attributes, the file must be saved with the proper format. It must be saved in the coordinate system specified above, as a GeoJSON file with UTF-8 character encoding. This results in a single ".geojson" file, which can be loaded into the Tygron Engine.

How to Convert a GIS file:

1. Open the GIS file in a GIS application, such as QGIS
2. If necessary, turn non-polygon shapes such as lines or points into polygons
3. If necessary, make sure all desired attributes are numeric
4. Save the file in GeoJSON format, using EPSG:3857, Pseudo Mercator, with encoding UTF-8

How to load a GeoJSON file into the engine

The Tygron Engine can be provided with a GeoJSON file, either by dragging-and-dropping the relevant file into the Tygron Engine, or by selecting "Import GeoJSON File" from the relevant Ribbon dropdown menu in the Tygron Engine. When using the dropdown menu, a file-selection screen will appear, so that the relevant GeoJSON file can be selected. When the file has been selected, or dropped into the Engine, a window will appear where its possible to select what kind of data the GeoJSON file should form in the project.

Depending on which option is selected, the options on the next window may vary, but a number are consistent for all desired forms of data.

File:GeoJSON option select.jpg

How many shapes intersect with the 3D world, and the "File selection" option.

File:GeoJSON option merge.jpg

The "Merge" option.

File:GeoJSON option filter.jpg

The "Filter" option.

File:GeoJSON option name.jpg

The "Name" option.