Landsat 7 ETM+ L1
About Landsat 7 ETM+ Collection 2 Level 1 Data
Mission Information
The Landsat 7 Enhanced Thematic Mapper (ETM+) sensor is carried onboard Landsat 7. It provides 7 spectral bands and 1 thermal band. Learn more about here.
Basic Facts
| Property | Info |
|---|---|
| Spatial resolution | 15 m for the panchromatic band and 30 m for the rest (the thermal band is re-sampled from 60 m) |
| Sensor | Enhanced Thematic Mapper (ETM+) with 8 spectral bands and 1 thermal band |
| Revisit time | 16 days |
| Spatial coverage | Whole globe |
| Data availability | Since May 1999 |
Accessing Data
To access data you need to send a POST request to our process API. The requested data will be returned as the response to your request. Each POST request can be tailored to get you exactly the data you require. To do this requires setting various parameters which depend on the collection you are querying. This chapter will help you understand the parameters for Landsat 7 ETM+ Level 1 data. For an overview of all API parameters see the API Reference.
Endpoint Locations
| Service | Notes |
|---|---|
| services-uswest2.sentinel-hub.com/api | Global coverage since April 1999. All scenes collected since May 30, 2003 have data gaps due to the Scan Line Corrector (SLC) failure. |
Data type identifier: landsat-etm-l1S
Use landsat-etm-l1[1] (previously LETML1) as the value of the input.data.type parameter in your API requests. This is mandatory and will ensure you get Landsat 7 ETM+ Level 1 data.
The collection is currently in the preview stage and might thus change.
[1]: landsat-etm-l1 stands for Landsat Enhanced Thematic Mapper Level 1.
Filtering Options
This chapter will explain the input.data.dataFilter object of the process API.
mosaickingOrder
Sets the order of overlapping tiles from which the output result is mosaicked. Note that tiles will in most cases come from the same orbit/acquisition. The tiling is done by USGS for easier distribution.
| Value | Description | Notes |
|---|---|---|
| mostRecent | selected by default. The pixel will be selected from the tile, which was acquired most recentl | |
| leastRecent | similar to mostRecent but in reverse order | |
| leastCC | pixel is selected from tile with the least cloud coverage metadata | note that "per tile" information is used here, each covering about a 31,000 sq. km area, so this information is only an estimate. |
maxCloudCoverage
Sets the upper limit for cloud coverage in percent based on the precomputed cloud coverage estimate for each tile as present in the tile metadata. Satellite data will therefore not be retrieved for tiles with a higher cloud coverage estimate. For example, by setting the value to 20, only tiles with at most 20% cloud coverage will be used. Note that this parameter is set per tile and might not be directly applicable to the chosen area of interest.
tiers
Selects product tiers.
| Value | Description |
|---|---|
| TIER_1 | selects Tier 1 products |
| TIER_1_AND_RT | selects Tier 1 and Real-Time products |
| ALL_TIERS | selected by default. selects Real-Time, Tier 1 and Tier 2 products |
Processing Options
This chapter will explain the input.data.processing object of the process API.
| Parameter | Description |
|---|---|
| upsampling | The same as for S2L1C. |
| downsampling | The same as for S2L1C. |
Available Bands and Data
Information in this chapter is useful when defining input object in evalscript.
Any string listed in the column Name can be an element of the input.bands array in your evalscript.
| Name | Description | Resolution |
|---|---|---|
| B01 | Blue (450-520 nm) | 30m |
| B02 | Green (520-600 nm) | 30m |
| B03 | Red (630-690 nm) | 30m |
| B04 | Near Infrared (NIR) (770-900 nm) | 30m |
| B05 | Shortwave Infrared (SWIR) 1 (1550-1750 nm) | 30m |
| B06_VCID_1, B06_VCID_2 | Thermal Infrared (10400-12500 nm) | 30m [1] |
| B07 | Shortwave Infrared (SWIR) 2 (2090-2350 nm) | 30m |
| B08 | Panchromatic (520-900 nm) | 15m |
| BQA | Quality Assessment band (QA) | 30m |
| QA_RADSAT | Radiometric Saturation and Terrain Occlusion QA Band | 30m |
| VAA | View (sensor) Azimuth Angle | 30m |
| VZA | View (sensor) Zenith Angle | 30m |
| SAA | Sun Azimuth Angle | 30m |
| SZA | Sun Zenith Angle | 30m |
| dataMask | The mask of data/no data pixels (more). | N/A [1] |
[1]: Thermal band is acquired at 60 meter resolution, but is resampled to 30 meter in delivered data product (source). More about two bands here.
[2]: dataMask has no source resolution as it is calculated for each output pixel.
Units
The data values for each band in your custom script are presented in the units as specified here. In case more than one unit is available for a given band, you may optionally set the value of input.units in your evalscript setup function to one of the values in the Sentinel Hub Units column. Doing so will present data in that unit. The Sentinel Hub units parameter combines the physical quantity and corresponding units of measurement values. As such, some names more closely resemble physical quantities, others resemble units of measurement.
The Source Format specifies how and with what precision the digital numbers (DN) from which the unit is derived are encoded. Bands requested in DN units contain exactly the pixel values of the source data. Note that resampling may produce interpolated values. DN is also used whenever a band is derived computationally (like dataMask); such bands can be identified by having DN units and N/A source format. DN values are typically not offered if they do not simply represent any physical quantity, in particular, when DN values require source-specific (i.e. non-global) conversion to physical quantities.
Values in non-DN units are computed from the source (DN) values with at least float32 precision. Note that the conversion might be nonlinear, therefore the full value range and quantization step size of such a band can be hard to predict. Band values in evalscripts always behave as floating point numbers, regardless of the actual precision.
The Typical Range indicates what values are common for a given band and unit, however outliers can be expected.
| Band | Physical Quantity (units) | Sentinel Hub Units | Source Format | Typical Range | Notes |
|---|---|---|---|---|---|
| Optical bands B01 - B05, B07, B08 | Reflectance (unitless) | REFLECTANCE [1] | UINT8 | 0 - 0.4 | Higher values in infrared bands. Reflectance values can easily be above 1. |
| Thermal infrared bands B06_VCID_1, B06_VCID_2 | Brightness temperature (kelvin) | BRIGHTNESS_TEMPERATURE [2] | UINT8 | 250 - 320 | Brightness temperature of roughly -20 to +50 C. Can reach outside this range in extreme environments. |
| BQA | Pixel quality assessment (unitless) | DN | UINT16 | bit-packed combination [3] | |
| QA_RADSAT | Radiometric saturation quality assessment (unitless) | DN | UINT16 | bit-packed combination [3] | |
| VAA | Angle (degrees) | DEGREES | INT16 | ||
| VZA | Angle (degrees) | DEGREES | INT16 | ||
| SAA | Angle (degrees) | DEGREES | INT16 | ||
| SZA | Angle (degrees) | DEGREES | INT16 | ||
| dataMask | N/A | DN | N/A | 0 - no data 1 - data |
[1]: Top of the Atmosphere Reflectance, which is obtained using the scene center sun angle.
[2]: Top of the Atmosphere Brightness Temperature.
[3]: Info here.
Catalog API Capabilities
To access Landsat product metadata you need to send search request to our Catalog API. The requested metadata will be returned as JSON formatted response to your request.
Collection identifier: landsat-etm-l1
Filter extension
eo:cloud_covercloud cover percentagelandsat:scene_idscene identifierlandsat:collection_categorycollection tier.T1for tier 1 (scenes with the highest radiometric and positional quality) andT2for tier 2 (scenes not meeting tier 1 criteria)
Distinct extension
date