Configuration and input data

This page describes the structure and format of inputs required for building MESSAGEix-Transport.

Both input data and configuration are stored in files under message_ix_models/data/transport/.

In most cases, these files are read from a subdirectory like …/data/transport/nodes/, where nodes denotes the message_ix_models node code list—for instance, “R12”—for which MESSAGEix-Transport will be built. This value is retrieved from the model.Config.regions setting on a Context object.

If the file data or configuration settings have a node (\(n\)) dimension, the file must be placed in such a subdirectory. Data for one node list is not usable for base models using a different node list.
For other data, a node list–specific file may be used. If none exists, the file of the same name in …/data/transport/ is used as a default. For example, …/data/transport/R12/set.yaml is used if it exists; if not, then …/data/transport/set.yaml is used.

Configuration and model structure

General (`config.yaml`, required)

The contents of this configuration file exactly map to the attributes of the class transport.Config. The class stores all the settings understood by the code for building, solving, and reporting MESSAGEix-Transport. The class also defines the default values for each setting (there is no file …/data/transport/config.yaml containing defaults.) It also has methods for reading the configuration from file; see the detailed description of Config.from_context().

The following is the configuration file for a base model with R12 nodes:

→ View data/transport/R12/config.yaml on GitHub

Technology code list (`technology.yaml`)

This file gives the code list for the MESSAGE technology concept/set/dimension. Some annotations (iea-eweb-flow, input, report) and the child hierarchy give information about technologies’ grouping according to transport modes.

→ View message_ix_models/data/transport/technology.yaml on GitHub

Code lists for other MESSAGE sets (`set.yaml`)

This file gives code lists for other MESSAGE concepts/sets/dimensions.

→ View message_ix_models/data/transport/set.yaml on GitHub

Code list `CL_TRANSPORT_SCENARIO`

This code list, stored in the file message_ix_models/data/sdmx/IIASA_ECE_CL_TRANSPORT_SCENARIO(1.0.0).xml, contains an SDMX code list for distinct MESSAGEix-Transport scenarios. The codes have IDs like LED-SSP1 that give a short identifier used in transport.workflow and elsewhere, and names that give a complete, human-readable description. Every code has all of following annotations:

SSP-URN

Complete URN of a code in ICONICS:SSP(2024) or another code list for the SSP used for sociodemographic input data and to control other settings in transport.build.

Example annotation text: 'urn:sdmx:org.sdmx.infomodel.codelist.Code=ICONICS:SSP(2024).1'

is-LED-Scenario

Example annotation text: True

repr() of Python True or False, the former indicating that “Low Energy Demand (LED)” settings should be used. See also Config.project.

EDITS-activity-id

Example annotation text: 'HA'

For EDITS (project.edits), the identity of an ITF PASTA scenario providing exogenous transport activity.

base-scenario-URL

Example annotation text: 'ixmp://ixmp-dev/SSP_SSP1_v1.1/baseline_DEFAULT_step_13'

URL of a base scenario used to build the corresponding MESSAGEix-Transport scenario.

Input data flows

The module transport.data contains a number of Dataflow instances, listed below, that each describe an input or output data flow. For each of the input data flows:

the Dataflow.path attribute gives a file path where a CSV file with input data is expected.
the Dataflow.key attribute gives the Key where loaded and transformed data from the file is available. (See also transport.key.exo, which allows access to all of these keys.) The key also expresses the dimensions of the input data flow.
The additional metadata explains the measure concept, units of measure, etc.

Through transport.build.main() (ultimately, transport.build.add_exogenous_data() and Dataflow.add_tasks()), each of these files is connected to a genno.Computer used for building MESSAGEix-Transport. Its contents are available as a quantity at the corresponding key, which is used as an input for further model-building computations.

Example: mode_share_freight

Contents of the file freight-mode-share-ref.csv are available at the key freight mode share:n-t:ref.
The key indicates the dimensionality of this quantity is \((n, t)\).
The corresponding CSV file has column headers “node”, “technology”, and “value”.

Not all files are currently or always used in model-building computations. Some submodules of transport use additional data files loaded or processed via other methods; see below under “Other data sources.” Most of the files have a header comment including the source of the data and units of measurement. In some cases—where a header comment would be too long—extended information is below. The git history of files, or the GitHub “blame” view can also be used to inspect the edit history of each file, line by line.

Quick links to each of the data flows: act_non_ldv activity_freight activity_ldv age_ldv cap_new_ldv class_ldv constraint_dynamic disutility demand_scale elasticity_f elasticity_p emi_intensity energy_other fuel_emi_intensity ikarus_availability ikarus_fix_cost ikarus_input ikarus_inv_cost ikarus_technical_lifetime ikarus_var_cost input_adj_ldv input_base input_ref_ldv input_share lifetime_ldv load_factor_ldv load_factor_nonldv mer_to_ppp mode_share_freight pdt_cap_proj pdt_cap_ref pop_share_attitude pop_share_cd_at pop_share_driver population_suburb_share speed t_share_ldv

message_ix_models.model.transport.data.act_non_ldv = <Dataflow wrapping 'DataflowDefinition=IIASA_ECE:DF_ACTIVITY(2025.3.11)'>

Fixed activity of non-LDV technologies. [dimensionless]

Key and dimensions: <activity:n-t-y:non-ldv+exo>
Input file at path: act-non_ldv.csv
Required for build: True