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creating-layers.md

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Creating Layers for Osmoscope Server

Creating a layer for use in Osmoscope Server is pretty easy. Osmoscope Server will periodically update your data layer (currently in GeoJSON format), maintain the statistics and publish it via it's internal web server. All you have to do is create a JSON file in the special format expected by Osmoscope-UI, and an additional overpass_query parameter, which defines the query to retrieve this layer's data.

The Layer File

For each layer you want to make available, you have to create a JSON file named layer_YOURLAYERNAME.json and place it in the config directory. This file contains the metadata about your layer. For the structure, see the Osmoscope UI documentation.

Define a property "overpass_query" which will be the query sent to the overpass server.

Note: You don't need to specify geojson_url and stats_data_url, as they will be generated by Osmoscope Server.

{
    "id": "ID OF YOUR LAYER",
    "name": "NAME OF YOUR LAYER",
    "doc": {
        "description": "MORE DETAILED DESCRIPTION OF THE LAYER",
        "why_problem": "MORE INFORMATION ON WHY THIS IS A PROBLEM (OPTIONAL)",
        "how_to_fix": "SOME INFORMATION ON HOW TO FIX THE ERROR (IF APPLICABLE)"
    },
    "updates": "HOW OFTEN THE DATA FOR THIS LAYER IS UPDATED",
    "overpass_query": "YOUR OVERPASS QUERY"
}

Defining the area of interest

In your overpass query, you may use a placeholder {{bbox}} for the area of interest of your query. It may be set via the setting OSMOSCOPE_AREA_OR_BOUNDINGBOX in config/config.py an accepts either a bounding box or an area:

OSMOSCOPE_AREA_OR_BOUNDINGBOX = 'area:3600062611'
OSMOSCOPE_AREA_OR_BOUNDINGBOX = '48.699,9.199,48.70,9.2'

Note: In development mode, you would probably use a rather small area/bounding box.

The DataSource File

Osmoscope Server generates a DataSouce File named layers.json , which references all your defined layers.

{
    "name": "OSMOSCOPE_SERVERNAME",
    "layers": [
        "URL OF FIRST LAYER",
        "URL OF SECOND LAYER",
        ...,
        "URL OF LAST LAYER"
    ]
}

To set the server name, change the OSMOSCOPE_SERVERNAME setting in config/config.py.

The Geodata

Osmoscope Server periodically updates the Geodata using the query defined in the layer file. The data is stored to a file data_YOURLAYERNAME.json . Per default, every layer is updated on Osmoscope Server start and at the time specified via the OSMOSCOPE_UPDATE_SCHEDULE crontab pattern in config/config.py. Note: It is recommended that you also configure OSMOSCOPE_REFERER and OSMOSCOPE_ADMIN_MAIL to support troubleshooting in case any of your queries causes issues at the Overpass server.

The Stats Data File

Osmoscope Server will maintain a CSV file named stats_YOURLAYERNAME.csv for each of your layers. After every successful data retrieval from overpass, the number of returned features is stored to it.