Gerardo Ezequiel Martín Carreño

Open-data architecture, spatial validation and governed release controls for area-level evidence.

As fractional CTO, I began with a technical audit and turned its findings into a staged implementation roadmap. I set technical strategy, designed the solution and data architecture, and led data engineering, bespoke spatial modelling and software delivery. The open-data proof of concept explored audience geography, location choices and media allocation. I introduced source and licence records, spatial holdouts, baseline comparisons and reproducible release checks, keeping customer-specific validation separate.

As fractional CTO, I began with a technical audit and turned its findings into a staged implementation roadmap. I set technical strategy, designed the solution and data architecture, and led data engineering, bespoke spatial modelling and software delivery. The open-data proof of concept explored audience geography, location choices and media allocation. I introduced source and licence records, spatial holdouts, baseline comparisons and reproducible release checks, keeping customer-specific validation separate.

• A technical audit and staged implementation roadmap informing the fractional CTO engagement.
• An open-data architecture with documented sources, processing and model provenance.
• Spatial holdouts and baseline comparisons built into validation.
• Release controls distinguishing research outputs from customer-specific validation.

Where the work stands: The engagement ended in October 2026. This case describes my delivered technical work, not ownership or proven customer impact. Detailed architecture and results remain confidential. Predictive signals do not establish causal effects.

A co-authored method for accounting for the materials flowing through and stored in a city, prepared for five CityLoops pilots, with my material-stock maps for Apeldoorn and Bodø.

At Metabolism of Cities, I co-developed and co-authored D4.4, the Urban Circularity Assessment Method, as one of four named authors. We combined material-flow accounts for two reference years with bottom-up building-stock accounting and 18 indicators. The method specified Sankey and dashboard outputs for facilitated application in Apeldoorn, Bodø, Mikkeli, Porto and Seville. I also developed CARTO maps of building material-stock estimates for Apeldoorn and Bodø, making the stock analysis explorable at building scale. I supported application across the five pilots, built Sankey and CARTO outputs and managed two analysts.

At Metabolism of Cities, I co-developed and co-authored D4.4, the Urban Circularity Assessment Method, as one of four named authors. We combined material-flow accounts for two reference years with bottom-up building-stock accounting and 18 indicators. The method specified Sankey and dashboard outputs for facilitated application in Apeldoorn, Bodø, Mikkeli, Porto and Seville. I also developed CARTO maps of building material-stock estimates for Apeldoorn and Bodø, making the stock analysis explorable at building scale. I supported application across the five pilots, built Sankey and CARTO outputs and managed two analysts.

• Named as one of four authors of CityLoops deliverable D4.4, Urban Circularity Assessment Method.
• Ten scale indicators and eight circularity indicators, paired with material-flow and bottom-up building-stock accounts.
• Public CARTO maps of building material-stock estimates in Apeldoorn and Bodø, with building typology and age-cohort views.
• A documented path from data collection and mass balancing to Sankey diagrams, indicators and a city dashboard, prepared for five pilot cities.

Where the work stands: The method and maps estimate urban flows and stocks from available evidence; they do not audit every tonne or survey the materials in each building. The Apeldoorn map credits 3DBAG building data and material intensities from Sprecher and colleagues. The two maps do not establish delivery of every proposed dashboard across all five pilots.

I co-authored CENTRINNO’s Cartography Alpha Version (D2.2, 2022): a shared method for nine European pilot cities to map local skills, materials and community networks.

At Metabolic, I co-authored D2.2, the Cartography Alpha Version, as one of six named authors. I helped shape a method connecting geographic context, community mapping and material flows. The report documents a clickable three-page website mock-up using Amsterdam as its example, alongside KUMU maps.

At Metabolic, I co-authored D2.2, the Cartography Alpha Version, as one of six named authors. I helped shape a method connecting geographic context, community mapping and material flows. The report documents a clickable three-page website mock-up using Amsterdam as its example, alongside KUMU maps.

• Named as one of six authors of CENTRINNO deliverable D2.2, Cartography Alpha Version, submitted on 31 January 2022.
• A common method connecting geospatial context, community mapping and material flows.
• Prepared KUMU maps, and a clickable three-page Amsterdam website mock-up as the worked example.
• A method diagram that separates the external Cartography Website from the internal KUMU platform, with top-down and bottom-up data meeting at pilot activities.

Where the work stands: D2.2 documents the 2021–2022 alpha scope. The public website has evolved since then and includes later pilot material produced by the wider programme. “Urban ecosystem” refers to resources, infrastructure and social relationships, rather than a biodiversity survey.