Data

In this section, we describe the data files used in the building creation process. This includes the GIS JSON file and the DAT files containing polygon and weight data.

1. GIS Data

The gis.json file is an essential part of the input data, containing a vector of building descriptions. Each building has attributes such as height, id, and outline, with geometric coordinates for constructing the building’s base.

1.1. Description

A gis.json file contains a vector of "building" objects, and each component of the vector needs a "height", "id", and "outline".

  • height is a double or float.

  • id is an integer.

  • outline is a category with another category called "geometry" that includes "coordinates_projection", a vector of polygons with holes. Each polygon with holes is a vector of polygons and holes, and what we use are the coordinates in the first polygon of the first polygon with holes.

1.2. Tree Structure

Here is a tree representation of the JSON structure:

  • building (Array)

    • 0 (Object)

      • height (Number) : 5.800000190734863

      • id (Integer) : 96857895

      • outline (Object)

        • geometry (Object)

          • coordinates_projection (Array)

            • 0 (Array)

              • 0 (Array)

                • 0 (Array)

                  • Vector of coordinate of each points of the polygon.

1.3. Example

Here is an example of a building description in a gis.json file:

{
    "building": [
        {
            "height": 5.800000190734863,
            "id": 96857895,
            "outline": {
                "geometry": {
                    "coordinates_projection": [
                        [
                            [
                                [
                                    7.679051876068115,
                                    48.564117431640625
                                ],
                                [
                                    7.679055690765381,
                                    48.56403350830078
                                ],
                                [
                                    7.679139137268066,
                                    48.56403732299805
                                ],
                                [
                                    7.679242134094238,
                                    48.56404113769531
                                ],
                                [
                                    7.679236888885498,
                                    48.56412124633789
                                ],
                                [
                                    7.6791534423828125,
                                    48.56412124633789
                                ],
                                [
                                    7.679152488708496,
                                    48.56413269042969
                                ],
                                [
                                    7.679120063781738,
                                    48.56413269042969
                                ],
                                [
                                    7.679121494293213,
                                    48.56412124633789
                                ],
                                [
                                    7.679051876068115,
                                    48.564117431640625
                                ]
                            ]
                        ]
                    ]
                }
            }
        }
    ]
}

2. Polygon and Weight Data

The DAT files provide geometric and weight data necessary for the building creation process. These files include:

  • Polygon Files: Z.dat, L.dat, rectangle.dat

    • Description: Contains the coordinates representing the building’s polygonal base.

    • Format: Plain text with space-separated values describing the vertices of the polygons.

  • Weight Files: Z_weight.dat, L_weight.dat, rectangle_weight.dat

    • Description: Contains weight data associated with each coordinate point in the polygon. Used primarily for processes such as roof extrusion.

    • Format: Plain text with numeric values representing weights.

2.1. Example Files

The following files were created for rapid testing and verification:

  • Test Files:

  • Z.dat and Z_weight.dat

  • L.dat and L_weight.dat

  • rectangle.dat and rectangle_weight.dat

2.1.1. Polygon Data Example (Z.dat)

The Z.dat file contains the coordinates of the building’s polygonal base. Here is an example:

8
0 0 0
0 4 0
-4 4 0
-4 8 0
4 8 0
4 4 0
8 4 0
8 0 0

2.1.2. Weight Data Example (Z_weight.dat)

The Z_weight.dat file contains the weight data for each point in the polygon, which is used for the roof extrusion process. If we want to create a straight wall it is important to use a very high value (10000 time bigger than average value) on the desired point. Here is an example:

1
16000
1
1
1
16000
1
1

3. Origin

For the results, a GIS JSON file was provided by Vincent Chabannes. This file contains detailed information about building geometries and was used to verify the accuracy of the building creation on district.



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