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cullen-molitor authored Jun 3, 2022
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Expand Up @@ -104,17 +104,38 @@ This repository can be cloned into the root directory of the MPC Hub. Within the

With MPC access as described above, a user has several options to begin creating their Random Convolutional Features (RCFs). An overview of the steps are as follows:

### Step 1 - Create a grid of points

Use the `dense_grid.ipynb` to execute the following steps:

- Create a uniform grid of points over the region of interest, or load a file containg the pre-produced latitude and longitude points to featurize
- Grid creation executed directly in the notebook:
- User selects a country or region and a grid will be created
- User can supply geometry or a country code can be specified to use the `geopandas` shapefiles
- For gridding the country of Zambia specifically, a user has two options: `equal angle` cells versus `equal area` grid cells
- `equal angle` grids are produced using the latitude/longitude geodetic coordinate reference system, EPSG 4326, which is based on Earth's center of mass
- results in each point representing a 0.01 by 0.01 degree grid cell that will be featurized
- This is roughly 1 km<sup>2</sup> (exact area varies by geographic location)
- This means a pre-processed, user-supplied file should have points with a minimum distance of 0.01 degrees to avoid overlap
- `equal area` grids are produced using the local coordinate reference system for the region of interest
- The local EPSG for the country of Zambia is the defualt, but the relevant EPSG for another region of interest may be supplied by the user
- User selects a country or region and a grid will be created
- User can supply geometry or a country code can be specified to use the `geopandas` shapefiles
- For gridding the country of Zambia specifically, a user has two options: `equal angle` cells versus `equal area` grid cells
- `equal angle` grids are produced using the latitude/longitude geodetic coordinate reference system, EPSG 4326, which is based on Earth's center of mass
- results in each point representing a 0.01 by 0.01 degree grid cell that will be featurized
- This is roughly 1 km<sup>2</sup> (exact area varies by geographic location)
- This means a pre-processed, user-supplied file should have points with a minimum distance of 0.01 degrees to avoid overlap
- `equal area` grids are produced using the local coordinate reference system for the region of interest
- The local EPSG for the country of Zambia is the defualt, but the relevant EPSG for another region of interest may be supplied by the user
-
### Step 2 - Select a featurization notebook

The featurization notebooks are:

- `rcf_multiband.ipynb`
- For use with the `landsat-c2-l2` satellite collection or `sentinel-2-l2a`
- `Sentinel_2_RGB.ipynb`
- For use with `sentinel-2-l2a` in only the visible spectrum.
- MUCH faster than other options
- `s2_l8_multiband.ipynb`
- For use with the `landsat-8-c2-l2` satellite collection or `sentinel-2-l2a`
- `landsat-8-c2-l2` is now deprecated in favor of the `landsat-c2-l2` collection

### Step 3 - Select Options

Options include selecting a satellite collection, the number of features to produce, the spectral bands, select the time period. These options are selected in the `rcf_multiband.ipynb`, `Sentinel_2_RGB.ipynb`, or `s2_l8_multiband.ipynb` notebooks.

- Select a satellite
- `landsat-8-c2-l2`
- `sentinel-2-l2a`
Expand All @@ -127,11 +148,15 @@ With MPC access as described above, a user has several options to begin creating
- Constrained by satellite mission timeline:
- Landsat 8: temporal coverage = February 2013 - present
- Sentinel 2: temporal coverage = June 2015 - present
- Run the notebook in full
- The notebook is configured to account for all of your desired inputs, but compute power may limit the extent of what is possible based on selected options
- For example, trying to featurize too many points in a single run may not only be slow, it may crash the kernel or cause a timeout or disconnect error

All of the above options can be configured in our featurization notebook, `rc_featurization.ipynb`, the primary notebook of this repository. Following these selections, the notebook can be run in full with the resulting workflow of:
### Step 3 - Run the notebook in full

- The notebook is configured to account for all of your desired inputs, but compute power may limit the extent of what is possible based on selected options
- For example, trying to featurize too many points in a single run may not only be slow, it may crash the kernel or cause a timeout or disconnect error

### Generalized notebook workflow

Following the above selections, the notebook can be run in full with the resulting workflow of:

1. Find an appropriate STAC item for each point (in parallel, using a spatially partitioned dataset of points)
2. Feed the points and STAC items to a custom Dataset that can read imagery given a point and the URL of a overlapping satellite scene
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