[GRASS-dev] Location EPSG code storage

[Maris Nartiss]

Hello all,
as EPSG codes have become de-facto standard way of identifying various
SRS'es in various services and other places, we need a way how to sore
locations EPSG code, if it's known. Currently when creating a new
location by EPSG code, this information gets lost. There is no easy
way how to determine current location EPSG code required to connect
any OGC WxS service. Comparing proj parameters from epsg file is not
failproof.

Options:
a) add a new key-value pair to PROJ_INFO
+ all information is stored in single place
+ projection information reading/writing code is already inplace
- it needs to be changed to deal with a new key-value pair
- breaks backwards compatibility
- EPSG code might not be known for most of (existing) locations
b) create a new file (epsg) in PERMANENT
+ doesn't affect current projection information management
- information lives separate from rest of projection information
- requires new functions to read/write this info

I would like to hear other developer opinion before any changes to
core parts are implemented.

Maris.