# satellite-change-detect

**Repository Path**: mirrors_mapbox/satellite-change-detect

## Basic Information

- **Project Name**: satellite-change-detect
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-09
- **Last Updated**: 2026-03-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# satellite-change-detect
=========================

![image](https://cloud.githubusercontent.com/assets/5084513/7424337/ad447c44-ef54-11e4-926e-c81329bdc7ae.png)

## tiledelta [very dev]

Given input directories of before and after image tiles, calculates relative change by:

 - Creating a grayscale image of the input bands
 - Calculates edges (roberts cross method)
 - Performs a principal component analysis on these two edge arrays
 - The second principal component of the above is then cut into classes, and either plotted w/ side-by-side before and after images, or
 - Vectorized into a geojson feature stream (useful for piping into [`tippecanoe`](https://github.com/mapbox/tippecanoe) for creation of Mapbox Vector Tiles)

### Install

`git clone` this repo and `cd` into it

then

`pip install -e .`

### Usage - api

`tiledelta.compareGreys(before_array, after_array, high_percentile, mid_percentile)`

### CLI usage

```
tiledelta comptiles [OPTIONS] FILEDIR COMPAREDIR

Options:
  -s, --sampling INTEGER (sampling stride to speed up vectorization)
  -f, --filetype TEXT (valid file extension)
  -p, --plotdir PATH (where to save plots to - optional)
  --help                  Show this message and exit.
```
NOTE: Input filenames need to fit this format!
```
{prefix}-{x}-{y}-{z}.{ext}
```

###  Tile w/ Tippecanoe

eg

```
tiledelta comptiles /Users/dnomadb/test_kath/ /Users/dnomadb/test_before/ -s 1 | tippecanoe -o test.mbtiles -z 15 -Z 11 -f
```
makes valid vector tiles expressing the degree of change for that location.