https://github.com/roblabs/make-latitude-longitude-lines
NPM script to generate latitude and longitude lines in GeoJSON format
https://github.com/roblabs/make-latitude-longitude-lines
geojson ndjson ndjson-filter ndjson-reduce node npm null-island
Last synced: 8 months ago
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NPM script to generate latitude and longitude lines in GeoJSON format
- Host: GitHub
- URL: https://github.com/roblabs/make-latitude-longitude-lines
- Owner: roblabs
- License: mit
- Created: 2017-12-29T01:41:29.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2018-09-02T22:34:55.000Z (about 7 years ago)
- Last Synced: 2025-02-14T06:14:58.986Z (8 months ago)
- Topics: geojson, ndjson, ndjson-filter, ndjson-reduce, node, npm, null-island
- Language: JavaScript
- Size: 488 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: LICENSE
Awesome Lists containing this project
README
## Make Latitude & Longitude Lines
NPM script to generate latitude and longitude lines in GeoJSON format
Usage
``` bash
# do this once
npm install --global
# npm uninstall --global
makeLatitudeLongitudeLines
# or if you want to install to the current folder
npm install
./cli.js
#
```
Generates GeoJSON that looks like this
``` javascript
// This example draws lines every 2.5 minutes
{
"type": "Feature",
"properties": {
"wgs84Degrees": "32° 50' 00\" N",
"wgs84Decimal": "32.833333"
},
"geometry": {"type":"LineString","coordinates":[[-180,32.833333],[180,32.833333]] }
},
{
"type": "Feature",
"properties": {
"wgs84Degrees": "32° 52' 30\" N",
"wgs84Decimal": "32.875000"
},
"geometry": {"type":"LineString","coordinates":[[-180,32.875],[180,32.875]] }
}
```
``` bash
makeLatitudeLongitudeLines > 2.5minutes.geojson
# convert to ESRI Shapefile
ogr2ogr -f "ESRI Shapefile" 2.5minutes.shp 2.5minutes.geojson
# clip to San Diego
BBOX="-117.34573 32.52852 -116.57119 33.05149"
ogr2ogr \
-t_srs EPSG:4326 \
-clipdst $BBOX \
-f GeoJSON sandiego.geojson 2.5minutes.geojson
```
### Examples
* Black Latitude & Longitude lines every 2.5 minutes
---
* Yellow UTM lines, every 1 Km
* Universal Transverse Mercator lines sourced from [NGA Office of Geomatics](http://earth-info.nga.mil/GandG/update/index.php?dir=coordsys&action=utm-1km-polyline-dloads)
-----
Filter the GeoJSON and just use the lines that cross at Null Island.
``` bash
# use `makeLatitudeLongitudeLines` instead of `cli.js` if you installed as global
# Generate
./cli.js > out.geojson
# Convert to ndjson
cat out.geojson | geojson2ndjson > out.ndjson
# filter and keep certain properties
ndjson-filter < out.ndjson 'd.properties.wgs84Decimal == "0.000000"' > null-island-grid.ndjson
# merge a stream into a feature collection
ndjson-reduce < null-island-grid.ndjson 'p.features.push(d), p' '{type: "FeatureCollection", features: []}' > null-island-grid.geojson
# view at geojson.io
geojsonio null-island-grid.geojson
# or, as a one-liner
cat out.geojson | \
geojson2ndjson | \
ndjson-filter 'd.properties.wgs84Decimal == "0.000000"' | \
ndjson-reduce 'p.features.push(d), p' '{type: "FeatureCollection", features: []}'
```
-----
### References
* Degrees Minutes Seconds to/from Decimal Degrees _ https://www.fcc.gov/media/radio/dms-decimal
* https://en.wikipedia.org/wiki/Decimal_degrees
* https://github.com/stevage/geojson2ndjson
* https://github.com/mbostock/ndjson-cli#filter
* https://github.com/mapbox/geojsonio-cli