tactile maps for street intersections

This work is related to the paper at the AGILE 2023 conference:

Semi-automated Pipeline to Produce Customizable Tactile Maps of Street Intersections for People with Visual Impairments Yuhao Jiang, María-Jesús Lobo, Sidonie Christophe, and Christophe Jouffrais AGILE GIScience Ser., 4, 29, 2023, https://doi.org/10.5194/agile-giss-4-29-2023

it's in binder!

open the binder link (and waaaait for it to load) it will load in to the jupyterlab intro page. on the left side, navigate to the notebook folder to find the notebooks (example_0.ipynb and example_1.ipynb), and run the examples in the notebooks!

the notebooks call the same scripts as the scripts in the scripts folder, but with some binder specific modifications.

set-up on a local machine

The scripts are developed on a Windows machine. It could work differently on other systems especially the pyQGIS / gdal part. Modify accordingly.

requirements

• geopandas (0.10.2)
• shaply (1.7.0)
• networkx (2.2)
• gdal/ogr (3010400)
• pyqgis ('regular' windows distribution or conda distribution)

Set up PyQGIS on Windows like this this or this (for conda). And in the qgis_env.json file, change the paths accordingly:

{
"PROJ_LIB": "C:\\OSGeo4W64\\share\\proj", //
"PROJ_DEBUG": "3", // can keep it like this, doesn't bother
"QT_QPA_PLATFORM_PLUGIN_PATH": "C:\\OSGeo4W64\\apps\\Qt5\\plugins",  // the Qt plug in folder
"PATH": ["C:\\OSGeo4W64\\apps\\qgis\bin", "C:\\OSGeo4W64\\apps\\Qt5\bin"],  // apps\\qgis\bin folder, and apps\\Qt5\bin folder 
"setPrefixPath": "C:\\OSGeo4W64\\apps\\qgis-dev", // apps\\qgis-dev folder
"PathAppend": "C:\\OSGeo4W64\\apps\\qgis-dev\\python\\plugins" // apps\\qgis-dev\\python\\plugins folder
}

A Braille font (Braille TBFr2007 IHS HEA thermo) is required to be installed on the machine to print the braille characters. This font can be downloaded here, and also provided in the templates folder.

file structure of the repo

repo/
├── example_0/  # intersection instance
│ ├── data/
│────└── 500/ # the geometries for 1:500 maps
│────└── 1000/  # geometries for 1:1000 maps
│────└── temp/ # temporary folder for processing results
│────└── map.osm  # the OSM file for this location
│────└── xyz.geojson # scale-independent geometries used during processing
│ └── param.json/  # the param file for this folder
│ ├── image/  # the output folder
├── scripts/  # scripts to be run in order
│ ├── 00_[...].py
│ ├── ...
│ └── 07_[...].py
├── templates/  # default templates and templates elements to print the map with
├── styles/  # default and some alternative styles defined in .qml
├── README.md

the param.json

There is a param.json file that contains the parameters used in the scripts. An example of this file and the parameters:

{
    "size_code": "A3",  // "A3", "A4", "A5_on", "A5_off"
    "center_lat": 48.58622,  // lat of the intersection center 
    "center_lon": 7.76322,  // lon of the intersection center
    "line_width": 1, // major line width, in mm
    "line_gap": 3,  // gap between parallel lines, in mm
    "area_gap": 5,  // gap between lines and areas, in mm
    "icon_size": 4,  // point icon size, in mm
    "icon_gap": 3,  // gap around the point, in mm
    "building_level": "rough",  // building generalization level, either "rough" or "detailed"
    "overlay_pref": "direct",  // point-line overlay preference, either "direct" or "displace"
    "object_list": ["building", "sidewalk_area"],  // ROADSIDE objects to include on the map. A3 maps allow max 8, A4 max 4, A5_on max 1, A5_off max 3. Exceeding the number = no map. Now, depending on the location, can choose from: [building, green, sidewalk_area, sidewalk_line, bus_stop] => the name has to be correct!
    "style_list": ["building_default", "line_2"],  // the symbol choice, name from the "style table", in the same order with the objects. 
    "lane_width": 3.5,  // default, don't change this. 
    "epsg": "3857"  // default, don't change this.
}

Now I don't have parameter value checks. So setting funny values would make it crash. Change them only when you know exactly what you are doing.

included style files

see styles\style_samples.png

default templates

(note: map legend is in french.)

One A3 and one A4 templates: "standard" templates with braille legend, template design following BANA guidelines.

two A5 templates:

• the A5_on template with braille legend: it only holds 3 features.
• the A5_off template that removes the braille legend for an interactive dot. Maps in this templates can be integrated with a tablet with a screen reader software that supports reading out the map items.

the scripts and the examples

general steps:

0. get data: export an OSM file, with the intersection in the center, of at least 40m x 40m. save the file under the this_location\data path.
1. modify the param.json:
   1. determine the out put map size with size_code
   2. change the center_lat and center_lon to the coordinates of the intersection center
   3. other things can be left as default. or modify if you know what you are doing
2. for each script, change base_folder = r'..\example_0' into the intersection folder path (where the param.json is)
3. run the scripts by the order number.

what each script does

Work in process so there would be bugs. Plus OSM data is unpredictable. Manually check the output from each step to see if it makes sense.

• 00a_prepare.py: make extent files needed for the following steps

• 00b_pre_process.py: extract data from map.osm to the data folder, do some other scale independent transformations on the street data.

• 01_street.py: transform the streets, get area sidewalk if available. outputs are in the folder of the corresponding scale

  • street_boundary_filled.geojson as the main street file
  • island_full.geojson if traffic island is present at this location
  • sidewalk_gen.geojson if area sidewalk is present

• 02_pedestrian_crossing.py: make pedestrian crossing lines

  • crossing_lines.geojson

• 03_island_split.py: before running this, check the island_full.geojson file and edit the "split" attribute for each island if the island is a cut-through

  • islands_split.geojson

• 04_point_overlay.py: place the bus stop, displace or direct overlay

  • bus_stop_overlay.geojson

• 05_sidewalk_lines.py: make sidewalk lines (if available)

  • sidewalk_lines.geojson => this is a tricky step and can go wrong easily now. manual curation needed.

• 06a_buildings.py: make generalized buildings

  • building_gen.geojson

• 06b_green.py: generalize the green areas

  • green_gen.geojson

• 07_assembly.py: put the geometry and the styles together in the template, output both png and pdf in the image folder

  • e.g. A3.pdf and A3.png

example 0: a simpler 4 way crossing, with area sidewalk data

A3 map, use this param setting:

{"size_code": "A3", 
"center_lat": 48.81802,
"center_lon": 2.32231,
"line_width": 1, 
"line_gap": 3, 
"line_area_gap": 4,
"area_gap": 5, 
"icon_size": 4, 
"icon_gap": 3,
"building_level": "rough",
"overlay_pref": "direct",
"object_list": ["building", "sidewalk_area", "bus_stop"],
"style_list": ["building_default", "sidewalk_area_default", "bus_stop_default"],
"lane_width": 3.5, 
"epsg": "3857"}

config the scripts with base_folder = r'..\example_0'

run scripts 00a - 00b - 01 - 02 - 04 - 06a - 07

output A3 map:

example 1: a more complex 5 way crossing with traffic islands

A3 map with detailed building footprint, use this param setting:

{"size_code": "A3", 
"center_lat": 48.58630,
"center_lon": 7.76322,
"line_width": 1, 
"line_gap": 3, 
"area_gap": 5, 
"icon_size": 4, 
"icon_gap": 3,
"building_level": "detailed",
"overlay_pref": "direct",
"object_list": ["building", "green", "sidewalk_line"],
"style_list": ["building_default", "green_default", "sidewalk_line_default"],
"lane_width": 3.5, 
"epsg": "3857"}

run the scripts 00a - 00b - 01 - 02

open the file data\500\islands_full.geojson and edit the split=1 for island with level_1 id 3, 11, 13 (or edit this in QGIS.)

continue to run the scripts 03 - 05 - 06a - 06b - 07

A3 map at output:

Same procedure (and edit the islands_full.geojson in the data\1000folder!) but with a slightly different size and style: use this param setting:

{"size_code": "A4", 
"center_lat": 48.58630,
"center_lon": 7.76322,
"line_width": 1, 
"line_gap": 3, 
"area_gap": 5, 
"icon_size": 4, 
"icon_gap": 3,
"building_level": "rough",
"overlay_pref": "direct",
"object_list": ["building", "green"],
"style_list": ["area_8", "sidewalk_area_default"],  // force the green area to use the sidewalk texture
"lane_width": 3.5, 
"epsg": "3857"}

get this A4 map

defining your own templates and symbols

Symbols can be defined as .qml files.

Templates can be designed in QGIS as qpt files. But, your own template might not work with the map assembly script. If you modify the exiting template, you can move items without changing their id.

sources and other

BANA guideline on tactile graphics

QGIS on conda