SAG Spatial reference system

From IMSMA Wiki
Jump to: navigation, search

For a complete list of available projections, issue the following query on an empty staging area (i.e. the one created after clicking on Validate Selections):

select *
from spatial_ref_sys

You may also consult to find the SRID that you would like to use. PostgreSQL is using the EPSG standard.

Adding spatial reference system

If you cannot find the reference system you would like to use in the dropdown list then you need to add it to the staging database. You consult to find the SRID that you would like to use.

SAG add ref sys.png

Example: Sri Lanka grid

  1. Compare your prj file with the definition on the website.
  2. When you are sure that you have find the correct projection/convertion file then click in the insert link.
    SAG add ref sys2.png

  3. Insert the reference system with a SQL tool like PGAdminIII or Navicat.
Note.jpg The Staging Area Generator will use the first number in the Insert statement in the Target SRID drop-down list.
Staging Area Generator GUI options.png

Error message when creating Geodata

Conversions/re-projections cannot be done between all coordinate systems/SRIDs. In fact, some coordinate systems are defined for and focus on a specific part of the world, and coordinates outside of this specific range cannot be represented. If this is the case, an error message such as the following will be displayed in the staging area generator progress window.

SAG geo error.png SAG geo error2.png

If you encounter this error, please verify whether the chosen SRID for re-projection and the coordinates in the source IMSMA are compatible. It could also be something wrong with references between tables in the IMSMANG database. You will find more information in the log file.