Open Location Code (Plus Codes)

Open Location Code (also known as Plus Codes) is a technology for encoding geographic locations into short, alphanumeric strings. It serves as a replacement for street addresses, particularly in areas without formal naming or numbering systems.

Key Characteristics:

• Area-based: Codes represent an area rather than a single point. Increasing the number of digits increases precision.
• Offline Capability: Full codes can be encoded and decoded completely offline without lookup tables or internet access.
• Similarity-based: Codes that are geographically close to each other tend to have similar character sequences.
• Shortening: Codes can be shortened relative to a reference location for easier communication (e.g., 6GCRPR6C+24 can be shortened if a reference location is known).
• Structure: Codes use a set of 20 digits that alternate between latitude and longitude. A + character is typically used after the first eight digits to distinguish them from postal codes.

Open Location Code (also known as Plus Codes) is a location encoding system designed to provide usable addresses for locations without street addresses.

Key features include:

• Length: Full codes are 10 to 11 characters long. Short forms (4 to 7 characters) can be used within approximately 50km of the original location (or 2.5km for 4-5 character codes) by providing a nearby city or locality.
• Structure: Includes a separator to distinguish codes from postal codes and aid human readability.
• Area-based: Codes represent areas rather than points. Truncating a code increases the area size while still containing the original location.
• Deterministic & Offline: Codes can be generated and decoded offline without any central infrastructure or provider dependency.
• Usability: The character set excludes easily confused characters and vowels to prevent accidental word formation and improve memorization.
• Proximity: Nearby locations share similar prefixes. There are discontinuities at longitude 180 and the north/south poles.
• Uniqueness: There is only one Plus Code for a given location and area size.

Open Location Code (also known as Plus Codes) is an open-source standard for expressing locations as short, easy-to-use alphanumeric codes. It serves as an alternative to traditional street addresses and latitude/longitude coordinates, especially in areas where street addresses are poorly defined or non-existent.

Key characteristics:

• Short and Memorable: Uses a higher number base (base 20) to keep codes shorter than latitude/longitude.
• Flexible Precision: Supports various levels of precision (e.g., a 10-digit code covers ~14m x 14m, while an 11-digit code is more precise).
• Offline Functionality: Codes can be generated and decoded without a data network.
• Visual Proximity: Codes that are close to each other are often alphabetically similar, allowing for visual comparison.
• Cultural Independence: Uses a specific character set designed to avoid common words and confusing characters.

To compile the datafield on Linux, you must have the Garmin Connect IQ SDK installed (e.g., in ~/connectiq) and a developer key (e.g., at ~/developer_key).

Generate a .prg file for the simulator

Run the following command to create a .prg file that can be used in the Connect IQ simulator:

~/connectiq/bin/monkeyc -w -y ~/developer_key -f monkey.jungle -o bin/PlusCodeDatafield.prg

Generate an .iq file for all devices

To build the .iq file containing binaries for each supported device (equivalent to the Export Wizard function), use the following command. This assumes the SDK is in ~/connectiq and your developer key is in ~/developer_key:

~/connectiq/bin/monkeyc -w -y ~/developer_key -f monkey.jungle -e -a ~/connectiq/bin/api.db -i ~/connectiq/bin/api.debug.xml -o PlusCodeDataField.iq -w -u ~/connectiq/bin/devices.xml -p ~/connectiq/bin/projectInfo.xml