1_baseline_generator_c2¶
This script generates a collection of harmonic baseline models for a user-specified Region of Interest, e.g. a US State.
Output specifications¶
Baseline models are generated per Path and are exported to specified Earth Engine Image Collection. The current implementation exports Path-based results clipped to a US State boundary from the TIGER: US Census States 2018 dataset, with states specified using their two-letter USPS code, e.g. 'MA' for Massachusetts.
| setting | description |
|---|---|
| VERSION | current version, 10-1 |
| ROOT | user repository folder |
| BASELINES_COLLECTION | new baselines Image Collection |
| STATE | USPS abbrev. e.g. MA |
Model parameters¶
Baseline models are fit to univariate time series of all high-quality Landsat observations. Though any band, index or transform can be used as inputs, testing has shown that vegetation indices, such as Tasseled Cap Greenness, are best suited for a harmonic modeling approach.
The following parameters are used to configure the baseline model runs:
| parameter | type | default | explanation |
|---|---|---|---|
| DEPENDENT | string | 'tcg' |
spectral index to use for model fitting |
| HARMONICS | string | 'h13' |
harmonic frequencies: 'h12' or 'h13' |
| START_YEAR | int | 1985 |
first year of first baseline |
| END_YEAR | int | 2019 |
last year of last baseline (inclusive) |
| WINDOW | int | 5 |
baseline length (moving window) |
| TS | string | 'full' |
Landsat observations: 'full' or '16d' |
| CC_THRESH | int | 80 |
maximum CLOUD_COVER_LAND filtering |
| BUFFER | int | 100 |
buffer distance to accomodate reprojection |
Results¶
Output images include harmonic regression terms, specifically the intercept (constant), slope (t), and two pairs of sine and cosine coefficients, as well as the model Root Mean Squared Error (rmse) and number of observations (nobs) used in model fitting. All results retain the UTM zone of Landsat inputs and have a 30m nominal pixel scale. Updated version buffers state boundaries to accomodate reprojection when generating assessment results.
Example output:
| Index | Name | Type | CRS | Nominal Scale |
|---|---|---|---|---|
| 0 | constant | double | EPSG:32619 | 30 |
| 1 | t | double | EPSG:32619 | 30 |
| 2 | cos_1 | double | EPSG:32619 | 30 |
| 3 | cos_3 | double | EPSG:32619 | 30 |
| 4 | sin_1 | double | EPSG:32619 | 30 |
| 5 | sin_3 | double | EPSG:32619 | 30 |
| 6 | rmse | double | EPSG:32619 | 30 |
| 7 | nobs | unsigned int32 | EPSG:32619 | 30 |
Properties:
| Property | Value |
|---|---|
| WRS_PATH | 10 |
| harmonics | h13 |
| name | tcg_1985-1989_h13_full |
| spectral_band | tcg |
| state | ME |
| time_series | full |
| version | 10-1 |
| year_end | 1989 |
| year_start | 1985 |