SIGMA X shows where Batam is actually growing. It reads satellite imagery and on-the-ground activity data for all 12 kecamatan (districts) of Kota Batam. Gemma 4 then acts as the analyst and gives each district a ranked verdict with its reasoning.

The problem

Batam is expanding fast through its free-trade and special economic zones, but checking real progress still means site visits and scattered datasets. A simple rule like “built-up index went up = growth” can’t tell a finished estate from a cleared lot.

How it works

• Satellite signals (Google Earth Engine), 2019→2025 plus a 2016→2025 decade view: NDVI, NDBI, MNDWI, Dynamic World built/bare land, Sentinel-1 radar, VIIRS night lights, Landsat land-surface temperature, Open Buildings, GHSL population and coastal reclamation.
• Ground truth (OpenStreetMap): counts of hotels and other lodging (hotels, motels, guest houses, hostels), plus F&B, retail and offices, for Jan 2016, Jan 2024 and today. All three dates come from the same source, the Overpass history API.
• Gemma 4 as the analyst: one multimodal call per district. Gemma gets the numbers as JSON, each compared with the Batam-wide change, plus 5 before/after and change images. It returns a verdict, a 0–100 growth score, its reasoning and evidence, a decade story, a 2028 outlook and a recommendation for BP Batam / Pemko Batam. A final call ranks all 12 districts and writes a city brief.
• Dashboard: a MapLibre map (light/dark) with a choropleth for any measure, filters, district profiles, a before/after image slider, trends, a data table with CSV export, and Ask ΣX: live Gemma 4 Q&A answered only from the evidence, in Bahasa Indonesia or English.

Why Gemma, not thresholds

Gemma has to reconcile signals that disagree, and it looks at the actual imagery to do it. For example: “NDBI rose but the image and the bare-land share show cleared ground, not finished structures: early stage, not realized growth.” Each district gets one of 6 verdicts: Growth Corridor, Early Stage, Underbuilt Demand, Stalled, Mature/Stable or Declining.

What it found

• Growth corridors: Bengkong (score 88), Nongsa and Sekupang (78 each).
• Stalled: Sagulung and Sei Beduk are building, but economic activity isn’t following.
• Early stage: Bulang is clearing land that hasn’t become buildings yet.
• Underbuilt demand: in Galang, electrification is outpacing formal building.
• Declining: Belakang Padang.

Limits

These are indicators, not official statistics. OSM counts, hotels included, partly reflect how much volunteers mapped, especially in 2016 when few Batam businesses were on the map. Sentinel-2 over Batam is cloud-limited (annual cloud-masked medians are used), and the population figures are modelled data.