Setting-up a New Map Layer – Part 5A: Simplifying Shapes in ArcMap
Demonstrates how to simplify a shapefile using ESRI's ArcMap software to create a GeoJSON. These GeoJSON files are used in Leaflet Maps in the IBIS-PH software and are necessary to display your data in a Leaflet map in IBIS.
Author: Chris Wenker, New Mexico Department of Health
Useful Resources:
From the US Census’s metadata for TIGER/Line Shapefiles:
“Coordinates in the TIGER/Line Shapefiles have six decimal places, but the positional accuracy of these coordinates may not be as great as the six decimal places suggest.”
https://www2.census.gov/geo/pdfs/maps...
@4:05, re: re: Coordinate reference system and decimal degrees
A discussion of coordinate reference systems could form an entire instructional video in itself. For the purposes creating a GeoJSON from a shapefile in a geographic coordinate system, entering a value of decimal degrees would also be appropriate for the Maximum Allowable Offset in ArcMap’s Simplify tool (e.g., 0.0005 DD ~ 55 meters). If that causes errors, though, a solution would be to re-project the source file to a projected coordinate system and Simplify that file (probably then requiring a re-projection back to a geographic coordinate system for use in Leaflet).
https://en.wikipedia.org/wiki/Decimal...
https://gis.stackexchange.com/questio...
https://gis.stackexchange.com/questio...
https://geonet.esri.com/thread/23160
https://en.wikipedia.org/wiki/Geograp...
http://desktop.arcgis.com/en/arcmap/1...
http://desktop.arcgis.com/en/arcmap/1...
Selecting a coordinate reference system during a GeoJSON export doesn’t seem to make much difference to the file’s performance in Leaflet, as long as it is a geographic coordinate system. Leaflet's default projection is EPSG: 3857, also known as "Google Mercator" or "Web Mercator."
https://gis.stackexchange.com/questio...
Another tool for vector simplification (untested by this author):
http://blog.mastermaps.com/2012/10/ma...
http://mapshaper.org/