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Ortho ready (L1C)

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Product description

The Ortho Ready (L1C) product is a 4-band imagery dataset designed for users who wish to perform their own orthorectification using a Digital Elevation Model (DEM) of their choice. The 16-bit, 4-band rasters (visual and near-infrared) are provided with Rational Polynomial Coefficients (RPCs). By combining the imagery, the RPCs, and a DEM, users can generate their own geometrically corrected, orthorectified images.

The product includes two main components: the image raster and its corresponding RPCs. The raster is delivered in GeoTIFF format, while the RPCs are conveniently duplicated for maximum compatibility. They are included as both embedded GeoTIFF tags within the raster and as a separate text file (e.g., image.tif and image_rpc.txt)1. This duplication ensures support across major GIS software, as some applications handle one format but not the other.

The RPCs are generated through a rigorous process. First, Ground Control Points are computed on the images against a reference2. A bundle block adjustment is then performed to minimize error and refine the satellite's position and orientation. The resulting physical sensor model is transformed into the simplified RPC polynomial format.

Each L1C raster has a fixed size that depends on the satellite generation (currently MarkIV and MarkV). The nominal ground resolution is also dependent on the satellite generation, orbit altitude, and the off-nadir angle of the capture. A single scene is delivered as multiple L1C images, with each image having a minimum overlap of 10% with the next.


An MarkIV L1C raster example.

Ortho ready product level is composed by a collection of anchor frames, these frames are 4-bands stacked images that contain continuous spectral information. With the available spectral and geometrical information the anchor frames or composites are constructed.


L1C product coverage.

Technical characteristics

Parameter

Mark IV

Mark V
Spectral bands

Blue : 450 - 510 nm
Green: 510 - 580 nm
Red : 590 - 690 nm
NIR : 750 - 900 nm

Blue : 450 - 517 nm
Green: 517 - 583 nm
Red : 597 - 690 nm
NIR : 759 - 890 nm

Frame size

5120 x 5120 pix

7000 x 9344 pix

GSD

1.03m 3

0.73m 3

Swath

5.2 Km 3

6.9 Km 3

Projection

Geographic coordinates at WGS84

⁠
Max Off-Nadir angle

± 25 deg

 ⁠
Image size

5120 x 5120 pixels

9344 x 7000 pixels
Image bit depth

Unsigned integer 16-bit

 ⁠
Image format

GeoTiff, LZW loseless compression

⁠

STAC item

Each L1C product contains multiple assets as well as metadata.

Assets

  1. thumbnail
  2. preview
  3. analytic
  4. rpcs
  5. cloud
  6. toa_factors

Non documented files or parameters should be ignored.

All assets follow the same basename template.

{DATE}_{TIME}_{SECOND_DECIMALS}_{SATELLITE}_{PRODUCT}_{PAYLOAD}_{VERSION}_{SUFFIX}.{EXTENSION}

  • DATE: Year(4 digits)month(2 digits)day(2 digits)
  • TIME: Hour(2 digits)minute(2 digits)second(2 digits)
  • SECOND_DECIMALS: All the decimal part from the timestamp seconds
  • SATELLITE: Satellite number
  • PRODUCT: L1C
  • PAYLOAD: MS for multispectral (4 bands)
  • VERSION: Check Changelog. Only present in the metadata asset.
  • SUFFIX: depends on the asset, can be empty.
  • EXTENSION: depends on the asset type.

All time values refer to the capture time in UTC. Hence the string 20220619_153346_938represent actually 2022-06-19 15:33:46.938.

Preview and thumbnail

drawing drawing









Raster

drawing The main raster, also called anchor frame, contains the ready to orthorectify data. It is a fixed size (check Technical specs) 4 bands (RGB and NIR), 16 unsigned bits raster. Its nodata value is 0. Its CRS defined by its RPCs is geographic WGS84. The RPCs are written inside the GeoTIFF as tags 1 and also as a different file in another asset. The raster format is GeoTIFF with LZW compression.










RPC

drawing The RPC 4 is a text file with the same name as the raster but having analytic_rpc as suffix. This is a common format to store this information that is understood by most software with orthorectification capabilities.





Cloud

Cloud masks are provided as single band GeoTIFFs. Check here for details.

CLOUD_MASKS

Example of clouds detected by Satellogic clouds detector.

TOA Factors

The L1C product raster is provided in Top Of Atmosphere (TOA) reflectance units (which take values between zero and one), encoded with a 10000 factor in order to fit them in a standard Tiff file. The conversion radiometric conversion factors are inherited from the input images(L1A) processing level.

Item metadata

Metadata is available per anchor frame. Common metadata can be found across composites of the same capture. The following table shows the description of the fields that are always present, together with an example. There may be other fields, but their presence is not guaranteed (most have the prefix satl-insights and satl-qa and correspond to internal image quality measures).

Prefix Field Name Description Example
n/a id Unique identifier for the STAC item 
20250930_025801_143_SN45_L1C_MS_2_0_0
n/a bbox Item bounding box 
[
  119.56896495671906,
  23.62805912936759,
  119.65730868533569,
  23.690097800133774
],
n/a assets List of the assets available for a given item 
{
  "preview": {
      "href": "link to the file",
      "type": "image/png",
      "roles": [
          "overview"
      ]
  },
  "rpc": {...},
  "cloud": {...},
  "analytic": {...},
}
n/a collection Collection name 
l1c
properties gsd Ground sample distance in meters 
0.90
properties eo : cloud_cover" Percentage of the image covered by clouds 
6.37
properties proj : shape Dimension of image in pixels (Height x Width) 
[7000, 9344]
properties instruments Options are MS for multispectral and HS for hyperspectral 
ms
properties datetime Capture time 
2025-09-06T18:43:23.402269+00:00
properties platform Satellite name that acquired the imagery 
newsat46
properties proj:epsg EPSG code of the Coordinate Reference System in which the image coordinates are 
4326
properties view : azimuth Viewing azimuth angle. The angle measured from the sub-satellite point (point on the ground below the platform) between the scene center and true north. Measured clockwise from north in degrees (0-360) 
166.1138
properties view : off_nadir The angle from the sensor between nadir (straight down) and the scene center. Measured in degrees (0-90). In case this angle cannot be computed, a value of -1 will be reported 
24.9490
properties view : sun_azimuth Sun azimuth angle. From the scene center point on the ground, this is the angle between truth north and the sun. Measured clockwise in degrees (0-360) 
72.3332
properties view : sun_elevation The estimated sun elevation measured at the target at the moment of the capture. Value in degrees. 
60
properties satl : satellite_generation Satellite generation category, mainly to differentiate between MarkIV and MarkV 
MarkV
properties satl : outcome_id The UUID of the entire capture this individual frame is part of 
ffbabb4f-3a97-45ec-bca3-0e4d56608c1c
properties satl : valid_pixel Percentage of pixels that are valid, from 0 to 100 
100
properties satl : exposure_sec Exposure time of capture in seconds 
0.002769
properties satl : product_name The product name 
L1C
properties satl : last_modified Timestamp when the product was last processed 
2025-09-30T04:30:38.122305+00:00
properties satl : transaction_id Internal processing transaction identifier 
l0-pipeline-cw5td
properties satl : product_version Product Version 
2.1.1
properties satl : software_version Internal software version used to process the product 
1.36.1
properties satl : satellite_altitude Satellite altitude in meters 
498240.1195991831
properties satl : ground_lock Boolean value that indicates if the processor was capable to find gcps at the capture 
true
properties satl-qa : qa_software_version Quality Control project SW version 
2.11.2
properties satl-qa : snr_blue Signal To Noise Ratio for the blue band, In case this metric cannot be computed, a value of -999 will be reported 
64.353
properties satl-qa : snr_green Signal To Noise Ratio for the green band, In case this metric cannot be computed, a value of -999 will be reported 
56.291
properties satl-qa : snr_red Signal To Noise Ratio for the red band, In case this metric cannot be computed, a value of -999 will be reported 
38.133
properties satl-qa : snr_nir Signal To Noise Ratio for the NIR band, In case this metric cannot be computed, a value of -999 will be reported 
23.073
properties satl-qa : burnt_blue Burnt pixels percentage for the blue band, In case this metric cannot be computed, a value of -999 will be reported 
0
properties satl-qa : burnt_green Burnt pixels percentage for the green band, In case this metric cannot be computed, a value of -999 will be reported 
0
properties satl-qa : burnt_red Burnt pixels percentage for the red band, In case this metric cannot be computed, a value of -999 will be reported 
0
properties satl-qa : burnt_nir Burnt pixels percentage for the NIR band, In case this metric cannot be computed, a value of -999 will be reported 
0
properties satl-qa : sharpness_fwhm_act_blue Full Width Half Maximum across-track value in pixels for blue band*, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : sharpness_fwhm_act_green Full Width Half Maximum across-track value in pixels for green band*, In case this metric cannot be computed, a value of -999 will be reported 
3.675
properties satl-qa : sharpness_fwhm_act_red Full Width Half Maximum across-track value in pixels for red band*, In case this metric cannot be computed, a value of -999 will be reported 
3.241
properties satl-qa : sharpness_fwhm_act_nir Full Width Half Maximum across-track value in pixels for NIR band*, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : sharpness_fwhm_alt_blue Full Width Half Maximum along-track value in pixels for blue band*, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : sharpness_fwhm_alt_green Full Width Half Maximum along-track value in pixels for green band*, In case this metric cannot be computed, a value of -999 will be reported 
3.008
properties satl-qa : sharpness_fwhm_alt_red Full Width Half Maximum along-track value in pixels for red band*, In case this metric cannot be computed, a value of -999 will be reported 
2.846
properties satl-qa : sharpness_fwhm_alt_nir Full Width Half Maximum along-track value in pixels for NIR band*, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : dr_blue Dynamic Range for the blue band* *, In case this metric cannot be computed, a value of -999 will be reported 
96.728
properties satl-qa : dr_green Dynamic Range for the green band* *, In case this metric cannot be computed, a value of -999 will be reported 
123.545
properties satl-qa : dr_red Dynamic Range for the red band* *, In case this metric cannot be computed, a value of -999 will be reported 
150.386
properties satl-qa : dr_nir Dynamic Range for the NIR band* *, In case this metric cannot be computed, a value of -999 will be reported 
81.207
properties satl-qa : alignment_ce95_blue The 95th percentile of the band-to-band alignment error between the green and blue bands is reported in meters, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : alignment_ce95_red The 95th percentile of the band-to-band alignment error between the green and red bands is reported in meters, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-qa : alignment_ce95_nir The 95th percentile of the band-to-band alignment error between the green and nir bands is reported in meters, In case this metric cannot be computed, a value of -999 will be reported 
-999
properties satl-insights : lulc_snow Land use/land cover percentage for snow 
0
properties satl-insights : lulc_urban Land use/land cover percentage for urban areas 
8.1
properties satl-insights : lulc_water Land use/land cover percentage for water 
77.3
properties satl-insights : lulc_forest Land use/land cover percentage for forest 
12.6
properties satl-insights : lulc_bareland Land use/land cover percentage for bare land 
0.5
properties satl-insights : lulc_cropland Land use/land cover percentage for cropland 
0
properties satl-insights : lulc_grassland Land use/land cover percentage for grassland 
1.5

* See Sharpness. Due to the provisional use of a feature mask that may fail to mask textured clouds, the reported sharpness metric should be considered fully reliable only in frames without cloud cover. A proper cloud mask implementation is pending.
* *Detailed documentation pending.

Packaging specification

If delivered as a package scene (via S3, FTP, or Zip download link), an L1C delivery contains the assets (see previous Product components section) of all/a subset of the L1C products that make up that scene. The metadata available in STAC API is included as a JSON file.

Additionally, every L1C package includes a digital signature to ensure data authenticity and integrity. Each package contains a manifest file and cryptographic signature that allows verification that the delivered data has not been tampered with. Learn more about Digital Signature verification.

.
├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_{task_id}.metadata.json
├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_{task_id}.zip
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}.json
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_analytic_rpc.txt
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_analytic.tif
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_cloud.tif
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_preview.png
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_thumbnail.png
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_toa_factors.json
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_manifest.txt
│   ├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_manifest.txt.sig
│   ├── ...
├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_preview.png
├── {date}_{time}_{second_decimals}_SN{sn}_{product_name}_{payload}_thumbnail.png

Known Issues

The L1C processor can occasionally produce images with anomalies that elude automated quality assurance (QA) checks. This section lists the most common of these known anomalies. While the list is not exhaustive, it will be updated in future editions of this document.

Discontinuities

This issue occurs when the bundle block adjustment process fails due to an insufficient number or a poor distribution of Ground Control Points (GCPs) and tie points. This is common in scenes dominated by water or clouds, where the algorithm cannot locate enough reliable features. In such cases, the L1C processor must fall back to using raw satellite telemetry, which can result in a misaligned or "non-straight" image stripe in the final output.

L1C result Expected result
L1C result Expected result

Blunders

Anomalies are discerned through a distinctive contrast inversion observed in the NIR band relative to others, with a notable tendency for this irregularity to impact road segments in closer proximity to agricultural fields.


Miss matching effect.

Failure in composition

Eventually the algorithm of composition may fail when creating a composite image. This problem should be isolated respect the surrounding composites, usually due to the need of improving the algorithm with specific image contents. It is expected that this issue will be less likely to be found with upcoming product versions, where the algorithm will progressively get more robust.


Isolated failure in image composition

Changelog

Version Release date Change log
2.2.0 17/11/2025
  • Adaptive anchor frame selection
  • Metadata fields harmonization
    • Renamed TOA factors asset fields for clarity:
      radiance_to_reflectance → removed
      toa_reflectance_to_radiance → added
      reflectance_scale_factor → added
    • Changed convention of view:azimuth to, the angle measured from the satellite point (point on the ground below the platform) between the scene center and true north. Measured clockwise from north in degrees (0-360). As defined in STAC View extension
  • Changed cloud mask codification, from [0: no_data, 1: valid_data, 255: cloud] to [0: no_data, 1: clear, 2: haze, 3: cloud]. New category "clear" replaces old category "valid_data". For further details check Cloud Mask section
2.1.0 27/08/2025
  • Include new cloud mask classification
2.0.0 20/05/2025
  • Deploys image quality metrics using standard SATELLOGIC library
    • Band to band alignment
    • SNR
    • Sharpness(FWHM)
    • Burned pixels
    • Dynamic range
1.7.1 06/02/2025
  • Improvements in the composites generation
1.6.0 28/11/2024
  • Set edtm as default dem
1.5.0 24/10/2024
  • Change band order in analytic image to blue, green, red, NIR
1.4.0 19/09/2024
  • Add product version to metadata/properties
1.3.0 06/05/2024
  • Add cloud mask asset
1.2.0 02/05/2024
  • Add azimuth and offnadir metadata fields
  • Geolocation improvements
  • Add satellite_generation and toa_factors asset
1.0.0 15/02/2024
  • Switch to L1A product as default input
0.10.0 15/01/2024
  • Geolocation improvement by fine-tuning gcp extraction
  • Allow MarkV processing
0.9.0 15/12/2023
  • Initial version

Imagery End User Rights Agreement and Terms of Use

All imagery products are delivered under Satellogic Imagery End User License Agreement. The terms and conditions of the agreement are available to customers and accessible online on the website under License Agreement.

  1. More info: gdal documentation ↩↩

  2. Reference image source: esri. Heights source: mapzen ↩

  3. Varies with altitude of the satellites and off nadir angle. Some Mark IV satellites will decay naturally in the following years, so a smaller GSD can be expected. Varies with off nadir angle too. ↩↩↩↩

  4. RPC definition ↩