Product Metadata
Each product package includes an XML metadata file (<stem>.xml) that describes the image raster: its acquisition parameters, processing level, geometric configuration, radiometric characteristics, processing versions and package contents. The package also includes an ENVI header (<stem>.tif.hdr) that makes the image readable in ENVI-based workflows. For the full list of files in the package, see Product Package.
The XML metadata file is organised into the sections described below. A sample metadata file and a sample ENVI header are provided at the end of this page.
Satellite Details
The first section of the XML metadata file (<Satellite_Details>) identifies the satellite platform and the sensor payload used for data capture. The root element of the file is <MetaData version="6.1">.
The Satellite field gives the spacecraft as Pixxel-<Satellite ID>, e.g. Pixxel-FF01. The Satellite IDs and their descriptions are listed below.
| Satellite ID | Description |
|---|---|
| TD01 | Technology Demonstrator 01 |
| TD02 | Technology Demonstrator 02 |
| FF01 | Firefly-1 |
| FF02 | Firefly-2 |
| FF03 | Firefly-3 |
The Sensor_Name field gives the sensor type. All sensors currently onboard Pixxel satellites are Visible-Near-infrared (VNIR) sensors, so this field is always VNIR.
Image Acquisition Details
The <Image_Acquisition_Details> section describes the conditions under which the raw image was captured, including the viewing and illumination geometry and the spectral characteristics of the bands.
| Field | Unit | Description |
|---|---|---|
Acquisition_Datetime | ISO 8601 | Date and time of the image capture in UTC (YYYY-MM-DDThh:mm:ssZ). |
Image_ID | String | Unique 10-digit image identifier. |
Altitude | km | Satellite altitude at the time of capture, derived from the orbit telemetry. |
Off_Nadir_Angle | ° | Off-nadir angle of the camera during capture. |
Scene_Center_Lat | °N | Latitude at the centre of the captured image. |
Scene_Center_Lon | °E | Longitude at the centre of the captured image. |
Sun_Azimuth_Angle | ° | Azimuth angle of the Sun, measured clockwise from north. |
Sun_Elevation_Angle | ° | Elevation of the Sun above the horizon. |
Earth_Sun_Distance | AU | Earth-Sun distance on the acquisition date. |
Number_Of_Bands | Count | Total number of spectral bands in the image (e.g. 45). |
Bands | String | Comma-separated list of unique band identifiers, in raster band order. |
Central_Wavelength | nm | Central wavelength of each spectral band. |
Bandwidth | nm | Spectral bandwidth (FWHM) of each band. |
Solar_Irradiance | W·m⁻²·µm⁻¹ | Exo-atmospheric solar irradiance of each band1. |
1 Source: https://www.nrel.gov/grid/solar-resource/assets/data/e490_00a_amo.xls
Processed Image Details
The <Processed_Image_Details> section describes the processed data product: its processing level, radiometric scaling, spatial projection, extent, quality and provenance.
| Field | Unit | Description |
|---|---|---|
Processing_ | String | Processing level of the product (L2A). |
Processing_ | String | Summary of the corrections applied to reach this level: Radiometrically corrected, Band registered, Georeferenced, Orthorectified, and atmospherically corrected Bottom-of-Atmosphere reflectance data. |
Output_ | String | Physical quantity represented by the pixel values (BOA Reflectance). |
Unit | String | Unit of the physical quantity (Unitless). |
Scale | Unitless | Factor by which pixel values are multiplied to obtain the physical quantity. |
Offset | Unitless | Offset added to the scaled pixel values to obtain the physical quantity (always 0). |
Map_ | String | EPSG code of the UTM map projection (e.g. EPSG:32643). |
MGRS_Grid | String | Military Grid Reference System (MGRS) grid reference of the scene centre, truncated to its first seven characters. |
Top_Left_Lat | °N | Latitude of the top-left corner. |
Top_Left_Lon | °E | Longitude of the top-left corner. |
Bottom_ | °N | Latitude of the bottom-right corner. |
Bottom_ | °E | Longitude of the bottom-right corner. |
Spatial_ | m | Pixel size (GSD) of the image product. |
Data_Type | String | Data type of the pixel values (Unsigned Integer 16-bit). |
No_ | Integer | Pixel value reserved for no data or padding (always 0). |
RGB_Bands | String | Band identifiers of the red, green and blue bands of the true-colour composite. |
Cloud_Cover | % | Percentage of valid pixels classified as cloud. Pixels flagged only as cloud edge are not counted. |
Captured_ | km² | Surface area enclosed by the image footprint. |
Image_ | MB | File size of the image raster (1 MB = 10⁶ bytes). |
SHA256_ | String | Secure Hash Algorithm 256-bit (SHA-256) hash of the image raster, for file integrity verification. |
Atmospheric_ | String | Model used for atmospheric correction, e.g. ISOFIT. |
Acknowledgement | String | Credits for the external data and software used to generate the product. |
Created_Time | ISO 8601 | Timestamp (UTC) at which the image raster was created. |
Version Details
The <Version_Details> section records the version of each processing stage used to generate the product. Together, these fields make the product reproducible and traceable to a specific processor release.
| Field | Format | Description |
|---|---|---|
Radiometric_Correction | X.Y.Z | Version of the radiometric correction (calibration coefficients and correction algorithms). |
Geometric_Correction | X.Y.Z | Version of the geometric correction and orthorectification model. |
Atmospheric_Correction | X.Y.Z | Version of the atmospheric correction model. |
Product_Package | X.Y.Z | Version of the product package format described in Product Package. |
Processor_ID | String | Short commit hash identifying the processor build. |
Product_Version | String | Combined product version (see below). |
The Product_Version combines the four stage versions into a single string of four dot-separated, 6-digit groups:
RRRRRR.GGGGGG.AAAAAA.PPPPPPHere R, G, A and P stand for the radiometric correction, geometric correction, atmospheric correction and product package versions. Each group is formed by zero-padding every component of the X.Y.Z version to two digits. For example, radiometric correction 3.1.4, geometric correction 3.0.3, atmospheric correction 3.0.5 and product package 3.0.6 give a Product_Version of 030104.030003.030005.030006. Released versions are listed in Product Versions.
Package Details
The <Package_Details> section lists the files that make up the product package. The XML file closes with a top-level <Copyright> element that holds the copyright and usage rights statement.
| Field | Description |
|---|---|
Image_Raster | Filename of the image raster (GeoTIFF). |
ENVI_Compatible_Header | Filename of the ENVI header. |
Image_Preview | Filename of the true-colour preview (JPEG). |
Image_Footprint | Filename of the footprint polygon (GeoJSON, EPSG:4326). |
Product_Classification_Layer | Filename of the PCL (GeoTIFF). |
Sample Metadata File
The following is a sample XML metadata file for an L2A product. Values are illustrative.
<?xml version='1.0' encoding='UTF-8'?>
<MetaData version="6.1">
<Satellite_Details>
<Satellite>Pixxel-FF01</Satellite>
<Sensor_Name>VNIR</Sensor_Name>
</Satellite_Details>
<Image_Acquisition_Details>
<Acquisition_Datetime>2001-12-30T05:12:40Z</Acquisition_Datetime>
<Image_ID>0000021756</Image_ID>
<Altitude unit="km">590.64</Altitude>
<Off_Nadir_Angle unit="deg">12.40</Off_Nadir_Angle>
<Scene_Center_Lat unit="deg-N">12.97500000</Scene_Center_Lat>
<Scene_Center_Lon unit="deg-E">77.57500000</Scene_Center_Lon>
<Sun_Azimuth_Angle unit="deg">151.62</Sun_Azimuth_Angle>
<Sun_Elevation_Angle unit="deg">49.85</Sun_Elevation_Angle>
<Earth_Sun_Distance unit="AU">0.9833</Earth_Sun_Distance>
<Number_Of_Bands>45</Number_Of_Bands>
<Bands>B002, B003, B004, B005, B006, B007, B008, B009, B010, B011, B012, B013, B014, B015, B016, B023, B024, B025, B059, B099, B100, B101, B102, B103, B111, B112, B113, B114, B115, B116, B117, B118, B119, B120, B125, B126, B127, B128, B129, B130, B131, B132, B133, B134, B135</Bands>
<Central_Wavelength unit="nm">475.6, 479.2, 482.4, 485.9, 489.8, 493.9, 497.5, 501.2, 505.2, 509.2, 512.6, 516.4, 520.5, 524.6, 528.1, 553.8, 552.8, 556.3, 660.0, 790.6, 793.8, 796.9, 800.2, 803.4, 827.0, 829.5, 832.2, 834.8, 837.4, 840.4, 843.2, 846.3, 850.0, 854.3, 868.3, 870.9, 873.3, 875.6, 877.8, 880.0, 882.1, 884.2, 886.2, 888.2, 890.0</Central_Wavelength>
<Bandwidth unit="nm">4.3, 4.4, 4.6, 4.5, 4.3, 4.0, 4.3, 4.5, 4.3, 4.2, 4.5, 4.6, 4.3, 4.2, 4.2, 4.5, 4.6, 4.5, 6.4, 6.0, 6.0, 6.1, 6.2, 6.2, 7.6, 7.5, 7.9, 8.0, 8.3, 8.2, 8.2, 8.6, 8.6, 8.2, 10.5, 11.1, 11.5, 11.5, 11.5, 11.4, 11.2, 11.0, 10.6, 10.2, 10.0</Bandwidth>
<Solar_Irradiance unit="W·m-2·µm-1">2093.5, 2097.5, 2079.3, 1943.0, 1984.8, 1996.5, 1967.3, 1909.2, 1967.0, 1950.5, 1923.3, 1789.7, 1831.5, 1878.0, 1839.0, 1889.5, 1887.3, 1871.3, 1536.2, 1162.3, 1141.3, 1141.7, 1138.8, 1129.0, 1067.0, 1059.0, 1046.6, 1038.3, 1038.0, 1030.1, 1023.3, 1000.1, 948.5, 954.5, 938.6, 934.5, 944.7, 948.7, 943.6, 939.1, 933.7, 930.2, 927.4, 924.8, 924.9</Solar_Irradiance>
</Image_Acquisition_Details>
<Processed_Image_Details>
<Processing_Level>L2A</Processing_Level>
<Processing_Description>Radiometrically corrected, Band registered, Georeferenced, Orthorectified, and atmospherically corrected Bottom-of-Atmosphere reflectance data</Processing_Description>
<Output_Quantity>BOA Reflectance</Output_Quantity>
<Unit>Unitless</Unit>
<Scale>2e-05</Scale>
<Offset>0</Offset>
<Map_Projection>EPSG:32643</Map_Projection>
<MGRS_Grid>43PGQ73</MGRS_Grid>
<Top_Left_Lat unit="deg-N">13.20000000</Top_Left_Lat>
<Top_Left_Lon unit="deg-E">77.30000000</Top_Left_Lon>
<Bottom_Right_Lat unit="deg-N">12.75000000</Bottom_Right_Lat>
<Bottom_Right_Lon unit="deg-E">77.85000000</Bottom_Right_Lon>
<Spatial_Resolution unit="m">5</Spatial_Resolution>
<Data_Type>Unsigned Integer 16-bit</Data_Type>
<No_Data_Value>0</No_Data_Value>
<RGB_Bands>B059,B024,B002</RGB_Bands>
<Cloud_Cover unit="percent">12.4</Cloud_Cover>
<Captured_Area unit="sqkm">2651.38</Captured_Area>
<Image_File_Size unit="MB">8642.17</Image_File_Size>
<SHA256_Checksum>5f2c9a71d04e8b3a6c1f7e92d58b0a4c3e6d9f1b2a7c8e05d4f3b6a9c1e2d7f8</SHA256_Checksum>
<Atmospheric_Model>isofit</Atmospheric_Model>
<Acknowledgement>Isofit has been used to create the final image product. Thompson et al., (2019) A unified approach to estimate land and water reflectances with uncertainties for coastal imaging spectroscopy. Remote Sensing of Environment,231,111198,2019.</Acknowledgement>
<Created_Time>2001-12-31T02:15:08Z</Created_Time>
</Processed_Image_Details>
<Version_Details>
<Radiometric_Correction>3.1.1</Radiometric_Correction>
<Geometric_Correction>3.0.3</Geometric_Correction>
<Atmospheric_Correction>3.0.5</Atmospheric_Correction>
<Product_Package>3.0.5</Product_Package>
<Processor_ID>a1b2c3d</Processor_ID>
<Product_Version>030101.030003.030005.030005</Product_Version>
</Version_Details>
<Package_Details>
<Image_Raster>FF01_20011230_00501045_0000021756_XL0.tif</Image_Raster>
<ENVI_Compatible_Header>FF01_20011230_00501045_0000021756_XL0.tif.hdr</ENVI_Compatible_Header>
<Image_Preview>FF01_20011230_00501045_0000021756_TCI.jpeg</Image_Preview>
<Image_Footprint>FF01_20011230_00501045_0000021756_FPT.geojson</Image_Footprint>
<Product_Classification_Layer>FF01_20011230_00501045_0000021756_PCL.tif</Product_Classification_Layer>
</Package_Details>
<Copyright>(C) Copyright 2026 Pixxel Space Technologies, Inc., El Segundo, CA 90245</Copyright>
</MetaData>Sample ENVI Header
The following is a sample ENVI header (<stem>.tif.hdr) for the same L2A product. Values are illustrative.
ENVI
description = {
Radiometrically corrected, Band registered, Georeferenced, Orthorectified, and atmospherically corrected Bottom-of-Atmosphere reflectance data}
samples = 12041
lines = 9841
bands = 45
header offset = 0
file type = TIFF
data type = 12
interleave = bsq
sensor type = Optical
byte order = 0
reflectance scale factor = 2e-05
map info = {UTM, 1, 1, 749275.00000000, 1460395.00000000, 5, 5, 43, North, WGS-84}
wavelength units = Nanometers
band names = { B002, B003, B004, B005, B006, B007, B008, B009, B010, B011, B012, B013, B014, B015, B016, B023, B024, B025, B059, B099, B100, B101, B102, B103, B111, B112, B113, B114, B115, B116, B117, B118, B119, B120, B125, B126, B127, B128, B129, B130, B131, B132, B133, B134, B135 }
wavelength = { 475.6, 479.2, 482.4, 485.9, 489.8, 493.9, 497.5, 501.2, 505.2, 509.2, 512.6, 516.4, 520.5, 524.6, 528.1, 553.8, 552.8, 556.3, 660.0, 790.6, 793.8, 796.9, 800.2, 803.4, 827.0, 829.5, 832.2, 834.8, 837.4, 840.4, 843.2, 846.3, 850.0, 854.3, 868.3, 870.9, 873.3, 875.6, 877.8, 880.0, 882.1, 884.2, 886.2, 888.2, 890.0 }
fwhm = { 4.3, 4.4, 4.6, 4.5, 4.3, 4.0, 4.3, 4.5, 4.3, 4.2, 4.5, 4.6, 4.3, 4.2, 4.2, 4.5, 4.6, 4.5, 6.4, 6.0, 6.0, 6.1, 6.2, 6.2, 7.6, 7.5, 7.9, 8.0, 8.3, 8.2, 8.2, 8.6, 8.6, 8.2, 10.5, 11.1, 11.5, 11.5, 11.5, 11.4, 11.2, 11.0, 10.6, 10.2, 10.0 }
solar irradiance = { 2093.5, 2097.5, 2079.3, 1943.0, 1984.8, 1996.5, 1967.3, 1909.2, 1967.0, 1950.5, 1923.3, 1789.7, 1831.5, 1878.0, 1839.0, 1889.5, 1887.3, 1871.3, 1536.2, 1162.3, 1141.3, 1141.7, 1138.8, 1129.0, 1067.0, 1059.0, 1046.6, 1038.3, 1038.0, 1030.1, 1023.3, 1000.1, 948.5, 954.5, 938.6, 934.5, 944.7, 948.7, 943.6, 939.1, 933.7, 930.2, 927.4, 924.8, 924.9 }
acquisition time = 2001-12-30T05:12:40Z
sun azimuth = 151.62
sun elevation = 49.85
data ignore value = 0
coordinate system string = {PROJCS["WGS 84 / UTM zone 43N",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",75],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","32643"]]}
default stretch = Gaussian