Tell more about max_err parameter in documentation for ST_Rescale

[strk]

The manual page for ST_Rescale doesn't tell what max_err parameter is for: ​http://postgis.net/docs/RT_ST_Rescale.html

[sunveersingh]

Hello, I would like to work on this issue, from where should I start?

[komzpa]

sunveersingh,

this issue is less trivial than previous ones.

1. find a file that creates raster extension in SQL, it is somewhere in raster directory and ends with .sql.in;

2. find there ST_Rescale, and see how it is defined. It may be written in SQL or in C. if it is written in SQL, read it there, otherwise it will have C function name - search all the files for it and start reading.

3. figure out what max_err is doing. What unit is it in? How is this error calculated? What happens when max_err is reached?

4. write a couple of sentences about it into raster file in doc/ as a separate new paragraph.

Does this look like a plan you can follow?

[sunveersingh]

komzpa, link to pull: ​https://github.com/postgis/postgis/pull/334

[komzpa]

In 17014:

Document maxerr in ST_Rescale.

Patch by Sunveer Singh.

Closes ​https://github.com/postgis/postgis/pull/334
Closes #2921