Can you set the PostGIS SRID when creating a Feature class through ArcCatalog?

Question

I have ArcSDE installed in a Postgresql database and I am using PostGIS geometry. I'm not a DB minded person so feel free to let me know if my process is not right.

I create my feature class in ArcCatalog (no probs) I then go into PgAdminlll to check out the new table. There are two things I notice when I check out my new table.

1) The record for my new table in the public.geometry_columns table has an SRID of -1. Is there any way to set the SRID during the feature class creation? If not how do I do this in PgAdminlll? Is it something like updateGeometry or addGeometry?

2) Also I notice that in PgAdminlll under the newly created tables properties there is no primary key assigned. So what I have been doing is assign the sde created objectid field as the primary key. Is this acceptable or should I be creating a new PK?

Thanks Ando

Answer 1

ad 1) If you view the contents of geometry_columns table (in PgAdmin3), you can simply double-click into the srid cell and type in any SRID you want. (If you have write access of course).

ad 2) Assuming that the SDE's objectid is kept unique and doesn't change, it shouldn't be a problem to use it as a primary key. I guess SDE doesn't create the tables with OIDs?

Answer 2

Registering a table containing an ST_Geometry column with ArcSDE

If the table does not contain any data and you register the table with ArcSDE but do not specify a valid SRID, the default SRID is used. For PostgreSQL and Oracle tables with ST_Geometry columns, the default is 0. The SRID 0 is present mainly for testing purposes; it does not actually assign a spatial reference. If you later try to add features that have a valid SRID other than 0, it will fail because the SRIDs are not the same. Once an SRID is assigned to a table, it cannot be changed; you have to delete the layer and re-create it with the correct SRID

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//006z00000030000000.htm

Answer 3

You can create Feature Classes in PostGIS using ArcGIS with the correct EPSG codes, with no need to correct the database.

Create a new folder under Projected Coordinates Systems, eg called epsg. Copy the original arcgis prj files into this folder. Rename the files to something meaningfull. Edit the files to reflect this name, and at the end of the line change the id to the epsg code.

Now, this epsg code will be available in Arcmap or arccatalog when creating a feature class. It will store the correct epsg code in the database too.

Example:

• create folder C:\Program Files (x86)\ArcGIS\Desktop10.0\Coordinate Systems\Projected Coordinate Systems\epsg
• copy file "Datum 73 Hayford Gauss IPCC.prj" into this new directory
• change name to "Datum 73 Modified Portuguese Grid 27493.prj"
• edit and change the name of the coord sys like this:
  PROJCS["Datum 73 Modified Portuguese Grid 27493",GEOGCS["GCS_Datum......
• edit and change the srid code to the epsg code:
  ...,AUTHORITY["EPSG",27493]]

While creating the new feature class, when selecting the coord system, navigate to projected coordinate systems, the new folder "epsg" is visible and you can see your new coord sys. Select it. Voila. The fc is correctly created.