archived

Moved to https://github.com/OpenSidewalks/opensidewalks-data

accessmap-seattle-data

Installation

City-specific dependencies

• The uwashington "region" requires the command line utility osmosis.

Local machine installation

0. (Optional) Install a virtualenv

   python3 -m venv venv source venv/bin/activate pip install --upgrade pip

1. Install GDAL

   On ubuntu:

   sudo apt install gdal-bin

2. Install dependencies pip install snakemake pip install -r requirements.txt

Docker-based installation

1. Build the container docker build -t accessmapdata .

Extract a single region's data

Note: if you used docker to install the dependencies, you can run a modified version of these commands by (1) including a volume bind (-v) to the region's directory and (2) running an extended command, e.g. bash -c "cd /bound/directory && snakemake -j 8".

1. Enter a region's directory cd cities/{region}

2. Fetch the source data snakemake -j 8 --snakefile Snakefile.fetch

3. Extract / build into a connected pedestrian network snakemake -j 8

Extract all regions and transform into transportation.geojson and regions.geojson

Note: if you used docker to install the dependencies, you can run a modified version of the merge command by (1) binding the entirey repo to a volume (-v) and (2) running an extended command: bash -c cd /bound/directory && python ./merge.py.

1. Extract each region one at a time. Their output directories will now be populated with a transportation.geojson.

2. In the main repo directory, run the merge script, which will (1) merge all transportation.geojson files into a single set of (otherwise unchanged) data and (2) create a regions.geojson that describes the different regions that were extracted (used by AccessMap). python ./merge.py

AccessMap data schema

This is the shared schema used to generation transportation.geojson. It is used by AccessMap for shared data (GeoJSON), map tiles (Mapbox Vector Tiles), and the routing engine on accessmap.io. It is intended to be an extension of the OpenMapTiles spec and uses the same licensing terms (CC-BY).

layers

transportation

This is the only way/linestring-based layer currently used by AccessMap, and it is a direct extension of the OpenMapTiles schema.

Fields

description

Unique to AccessMap

This is not from the original OpenStreetMap data, but is a free-form text field derived from spatial and other metadata, e.g. using street data one might have a description of "NE of Main St".

footway

Unique to AccessMap

The original value for footway on OpenStreetMap. This allows differentiation between different classes of footway. Possible values:

• crossing
• sidewalk

crossing

Unique to AccessMap

Values for the crossing key in OpenStreetMap as applied to ways. This is not the original value, as there is fragmentation in tagging standards regarding marked crossings and they all roughly mean the same thing. Therefore, uncontrolled and zebra are all converted to marked. Possible values:

• marked
• unmarked

kerb_raised

Unique to AccessMap

This is an inferred quantity based on either network analysis or spatial proximity of a crossing to lowered curbs, and should be interpreted as indicating that using this path requires crossing over a raised curb interface. This quantity is useful for visualization - which paths required traversing a curb? Possible values:

• 1
• 0

incline

Unique to AccessMap

This is not the original OpenStreetMap tag for incline, which would indicate the maximum incline over a path, but is instead an estimated minimum incline based on DEM data over the length of the path. The original OpenStreetMap incline tag is fairly rare on footways to begin with. The value represents a "rise over run" estimate, i.e. a fraction of elevation gain/loss versus distance, and is directional: a negative value indicates downhill in the direction of the way whereas a positive value indicates uphill.

surface

Unique to AccessMap

This is the original surface key in the OpenStreetMap data. It indicates the surface of the way being traversed, such as concrete vs. grass. Possible values:

• asphalt
• concrete
• gravel
• grass
• paved
• paving_stones
• unpaved

length

Unique to AccessMap

This is the calculated length of the way, in meters, according to the Haversine formula (Great-Circle Distance). This calculation is typically left up to consumers of geometry data, as the geometry is, itself, furnished for geometrical analysis. This is likely how AccessMap should also handle these data, but for now length is precalculated.

foot

Unique to AccessMap

Original value of the foot key if it is set to yes or no. Possible values:

• 1
• 0

opening_hours

Unique to AccessMap

Original value of the opening_hours tag.

elevator

Unique to AccessMap

Whether the path uses an elevator for vertical movement, e.g. building paths. Possible values:

• 1
• 0

width

Unique to AccessMap

Original value of the width tag if it has no units (unit conversion not yet supported) - implied unit is meters.

layer

The original layer tag on OpenStreetMap, this refers to the relative z-order of map elements. This is an integer that can be negative, so e.g. layer=0 is above layer=-1.

service

The original value of the service tag on OpenStreetMap, this refers to service ways, which includes driveways, parking lots, and alleys. Possible values:

• alley
• crossover
• driveway
• parking_aisle
• siding
• spur
• yard

level (not used)

This is not yet used, but should be in future specs. It is an integer indicating the associated building level of a feature, including footways - e.g. a pathway around part of a building.

brunnel

This contains information on the bridge/tunnel/ford tags. Possible values:

• bridge
• ford
• tunnel

indoor

Whether the pathways is indoor or not (this is not yet implemented). Possible values are stated to be '1' in the OpenMapTiles spec - presumably the key doesn't exist at all if indoor=no. Possible values:

• 1

ramp (not used)

This is an ambiguous / undefined tag for pedestrian ways and is not currently used by Accessmap. We do not use this OpenMapTiles field.

subclass

The highway=* subclass of the displayed way. The only values used by AccessMap are:

• cycleway
• footway
• path
• pedestrian
• steps

There are plans to add corridor for indoor routing.

barriers

Unique to AccessMap

This is a layer not found in the OpenMapTiles spec that should, ideally, be contributed back into separate appropriate layers. It is focused on pedestrian features that pose potential barriers (though depending on the values, some are helpful infrastructure). Note that all features in the barriers layer are points.

Fields

kerb

The value of the original kerb tag. Possible values:

• flush
• lowered
• raised
• rolled

tactile_paving

The value of the original tactile_paving tag. Possible values:

• 1
• 0