Satellite Before/After Comparison (NASA)

Before/after satellite comparison of the same area on two dates from NASA GIBS true-color imagery (MODIS or VIIRS, about 250 m per pixel): one side-by-side JPEG with date labels plus pixel-based change metrics (share of changed pixels, brightness change) and a cloud, haze and snow estimate for each date, with a plain-language reading that says whether the change is likely real or just weather. For floods, wildfires and burn scars, drought and lake levels, snow cover, deforestation or construction at regional scale. Params: place ("Valencia, Spain") or lat + lon + radius_km (5 to 500, default 50) or bbox, date_before (default one year before date_after), date_after (default yesterday), layer, width (64 to 768 per image, default 384), include_separate.

Run free trial ↗1 free call per day with the example input. Paid: $0.015 USDC, no limit.

Call it

import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agentsvc.io/api/v1/proxy/satellite-compare", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({"lat":-18.75,"lon":-67.1,"radius_km":50,"date_before":"2014-05-10","date_after":"2016-05-10","width":256}),
});
const { data, payment } = await res.json();  // payment.transaction = on-chain receipt

Input

Field	Type	Description
bbox	array
lat	number
lon	number
radius_km	number = 50
layer	modis_terra \| modis_aqua \| viirs_snpp \| viirs_noaa20 = "modis_terra"
width	integer = 384	Width of each of the two images; the composite is 2 x width + 8 px
place	string	Place name instead of coordinates, e.g. "Valencia, Spain" (GeoNames, cities and towns)
date_before	string	YYYY-MM-DD, default 365 days before date_after
date_after	string	YYYY-MM-DD, default yesterday
include_separate	boolean = false	Also return both images separately as base64

Output

Field	Type	Description
image_base64	string
mime_type	string
width	integer
height	integer
layout	string
bbox	object
date_before	string
date_after	string
layer	string
layer_id	string
change	object
size_bytes	integer
attribution	string
note	string

Example response (data)

{
  "image_base64": "/9j/2wBDAAYEBAUEBAYFBQUG…",
  "mime_type": "image/jpeg",
  "width": 520,
  "height": 264,
  "layout": "side_by_side: left = date_before, right = date_after, date labels on top",
  "bbox": {
    "min_lat": -19.2005,
    "min_lon": -67.5757,
    "max_lat": -18.2995,
    "max_lon": -66.6243
  },
  "date_before": "2014-05-10",
  "date_after": "2016-05-10",
  "layer": "modis_terra",
  "layer_id": "MODIS_Terra_CorrectedReflectance_TrueColor",
  "change": {
    "mean_brightness_change_pct": 7.3,
    "changed_pixels_pct": 20.1,
    "before": {
      "cloud_or_snow_pct": 0.5,
      "cloud_haze_or_snow_pct": 8.6,
      "no_data_pct": 13,
      "mean_brightness": 42.6
    },
    "after": {
      "cloud_or_snow_pct": 6.4,
      "cloud_haze_or_snow_pct": 18.3,
      "no_data_pct": 0,
      "mean_brightness": 49.8
    },
    "reliable": true,
    "reading": "Visible change in part of the area (for example water level, burn scars, flooding, snow or fields). Check the image."
  },
  "size_bytes": 22150,
  "attribution": "NASA EOSDIS GIBS / Worldview",
  "note": "Daily true-color mosaics at about 250 m per pixel. Change metrics are computed from pixels and are indicative only; seasons, sun angle, clouds and smoke all count as change."
}