Overview
Coordinates in OpenGround are defined using a Proj.4 string—a line of text that specifies how to convert between Latitude/Longitude and a selected Coordinate Reference System (CRS). This guide explains the terminology, how to find and add coordinate systems, and how to configure them in OpenGround.
Terminology:
- Coordinate Reference System – Defines the Easting/Northing pair by projecting global Latitude/Longitude values onto a flat plane. Commonly used in engineering and construction projects for localized accuracy.
- Examples: UTM Grids, State Plane Coordinates, Grid Coordinates.
- Datum: A datum is the reference point or model used to define the coordinate system. Different datums can result in different coordinate values for the same location.
- Examples: NAD27, NAD83, GRS80
- Easting/Northing – Represents a location on a 2D plane, defined by the selected coordinate system. Units are typically in meters, feet, or survey feet.
- Geographic Coordinate System – Defines a location using Latitude/Longitude on the surface of a sphere (the Earth). Commonly used in GPS and global mapping applications.
- Latitude/Longitude – Specifies a location on the Earth’s surface using angular measurements. Units are typically displayed as Decimal Degrees (DD) or Degree Minutes Seconds (DMS).
Adding a Coordinate System in OpenGround
To add a coordinate system using a Proj.4 string:
Step 1: Find the Coordinate System
Use one of the following resources to locate the desired CRS:
- http://epsg.io/ – EPSG Codes Only.
- https://spatialreference.org/ – Contains EPSG and ESRI Codes.
Once located, scroll to the Proj.4 section and copy the string.
Step 2: Add the Coordinate System in OpenGround Professional
- Navigate to: System > Coordinate Systems > Add
- In the dialog window, enter the following:
- CRS Value: The EPSG code (e.g.,
EPSG:26919) - Name: A descriptive name for the coordinate system (e.g.,
NAD83 / UTM zone 19N) - Proj.4 String: Paste the copied Proj.4 line
Example:
+proj=utm +zone=19 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs- Check the "Is Active" option.
- Click Save.
The coordinate system is now available for use in your OpenGround projects.
Further Reference
For more information on spatial reference systems, visit:
Spatial Reference System - Wikipedia