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https://github.com/chasenicholl/geohash-signature
Generate a Geohash signature from a shape
https://github.com/chasenicholl/geohash-signature
Last synced: about 2 months ago
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Generate a Geohash signature from a shape
- Host: GitHub
- URL: https://github.com/chasenicholl/geohash-signature
- Owner: chasenicholl
- License: gpl-2.0
- Created: 2017-12-26T01:39:27.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2017-12-31T15:54:01.000Z (about 7 years ago)
- Last Synced: 2024-10-30T06:58:44.315Z (3 months ago)
- Language: Python
- Size: 974 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: COPYING
- Authors: AUTHORS.txt
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README
# Geohash Signature [](https://circleci.com/gh/chasenicholl/geohash-signature/tree/master)
Do you need to know what Geohashes make up a Polygon, or run along a LineString _**fast**_? Generate a **Geohash Signature** from _any_ shape using the `geohash_signature` module!
Supports Python 2.7 and 3.5+ _(but please use 3, come on now people)_
#### _Signatures Visualized_
## Requirements
- Python >=2.7 (including Python 3.x) (>=3.5 recommended)
- Shapely >= 1.6
- python-geohash >= 0.8.5
- geojson >= 2.3.0
## Installation
```python
python setup.py install
```
## Performance
`within` performances slightly slower then `intersects` because `intersects` uses the fishnet algorithm to chop up the shape so it can be calculated in parallel.
The larger the shape and/or smaller the Geohash Level will result in dramatic performance decreases. The sweet spot tends to be around a signature with a Geohash Level of 10.
#### Results:
Generating a Geohash Signature using the `intersects` method against a Polygon with dimensions of `152.9m x 152.4m` on an 8 core machine
- intersects(POLYGON, 10)
- 0m1.806s
- results in 33,540 geohashes
- intersects(POLYGON, 11)
- 0m26.470s
- results in 1,052,676 geohashes
- intersects(POLYGON, 12)
- 19m55.589s
- results in 33,579,012 geohashes
## API
### **intersects**(shape, geohash_level=10, compress=False)
### **within**(shape, geohash_level=10, compress=False)
- shape: Shapely Shape or GeoJSON dictionary
- geohash_level: 1-12 [Default: 10]
- compress: True|False [Default: False]
Takes a Shapely Shape or GeoJSON dictionary, and returns a set of Geohashes that **intersect** _or are_ **within**. Defaults to Geohash level of 10. You can also optionally compress the response to its common prefix and components.
### **geohash_feature_collection**(geohashes, save_to=None)
- geohashes: A \ or \ of Geohashes
- save_to: Optionally write the FeatureCollection to a file.
Helper function to generate a Feature Collection. Takes a \ or \ of Geohashes and returns them as a Feature Collection of Polygons _or_ optionally you can save that Feature Collection as a GeoJSON file.
### **compress_geohashes**(geohashes)
- geohashes: A \ or \ of Geohashes
Helper function to compress hashes after the fact. Takes a \ or \ of Geohashes and returns a tuple (common_prefix, set(parts)).
## Using the Module
```python
import geohash_signature
from shapely.geometry import Polygon
# Create a shapely shape
COORDINATES = [[-73.99603330, 40.73283237],
[-73.99610310, 40.73287904],
[-73.99604151, 40.73295838],
[-73.99596555, 40.73293815],
[-73.99578489, 40.73290082],
[-73.99578489, 40.73290082],
[-73.99576436, 40.73283704],
[-73.99582184, 40.73275458],
[-73.99591423, 40.73275147]]
SHAPE = Polygon(COORDINATES)
# OR pass GeoJSON dictionary
# SHAPE = {
# "type": "Polygon",
# "coordinates": [COORDINATES]
# }
# Returns a set() of Geohashes
GEOHASHES = geohash_signature.intersects(SHAPE, geohash_level=10)
GEOHASHES_WITHIN = geohash_signature.within(SHAPE, geohash_level=10)
```
Optionally you can compress the Geohash response. `intersects` and `within` have an optional `compress` property, or you can manually compress using `compress_geohashes` method.
This will return the Geohashes in a tuple (common_prefix, {"part", "part", "part"})
i.e. ```("dr5rspj", {"tzg", "tzp", "tzq", "tzr"})```
```python
import geohash_signature
from shapely.geometry import Polygon
# Create a shapely shape
COORDINATES = [[-73.99603330, 40.73283237],
[-73.99610310, 40.73287904],
[-73.99604151, 40.73295838],
[-73.99596555, 40.73293815],
[-73.99578489, 40.73290082],
[-73.99578489, 40.73290082],
[-73.99576436, 40.73283704],
[-73.99582184, 40.73275458],
[-73.99591423, 40.73275147]]
SHAPE = Polygon(COORDINATES)
# intersects & within accept an optional compress attribute
PREFIX, COMPONENTS = geohash_signature.intersects(SHAPE,
geohash_level=10,
compress=True)
# Or manually compress the results
PREFIX, COMPONENTS = geohash_signature.compress_geohashes(GEOHASHES)
```
## Using the CLI
You can pass GeoJSON as a string or a file path.
```
Usage:
geohash-signature
[--geohash_level=]
[--filter=]
[--compress]
Options:
geojson Path to GeoJSON file or String. (required)
--geohash_level=<1-12> The resolution of the signature. (default: 9)
--filter= Which signature filter to use. (default: intersects)
--compress Compress the results (optional)
```
```
$ geohash-signature /path/to/poly.geojson \
--geohash_level=10 \
--filter=intersects \
--compress
```
## References
[Geohash Levels](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-geohashgrid-aggregation.html#_cell_dimensions_at_the_equator "Geohash Levels")
## License
This General Public License does not permit incorporating your program into
proprietary programs.
In simple words, if you are using this **NOT FOR PROFIT**, skies the limit. If you plan to use this in a commerical application, please reach out to me for licensing. Think how MySQL works.