[gdal-dev] questions about S-57

[Randy]

Hi Frank and list,
Thanks for your prompt and explicit response, I think I see now.

Best regards,
Randy

-----Original Message-----
From: Frank Warmerdam [mailto:warmerdam at pobox.com] 
Sent: Monday, March 15, 2010 7:09 PM
To: Randy
Cc: GDAL/OGR mailing list
Subject: Re: [gdal-dev] questions about S-57

Randy wrote:
> Hi Frank and list,
> 
> I have several questions which are not relevant to GDAL/OGR itself, but 
> S-57 format.
> 
> Wish any hint, thanks!
> 
> NO.1
> 
> I'd like to know whether PRIM is as same as NAME_RCNM? If not, what's 
> the difference between the two?

Randy,

Reviewing a WRECKS feature I see they are not, I have:

   PRIM (Integer) = 1
   NAME_RCNM (IntegerList) = (1:110)
   NAME_RCID (IntegerList) = (1:498)

So, RCNM is 110 (isolated node) and PRIM is 1 (point feature).  From
the include file:

/* -------------------------------------------------------------------- */
/*      RCNM values.                                                    */
/* -------------------------------------------------------------------- */

#define RCNM_FE         100     /* Feature record */

#define RCNM_VI         110     /* Isolated Node */
#define RCNM_VC         120     /* Connected Node */
#define RCNM_VE         130     /* Edge */
#define RCNM_VF         140     /* Face */

/* -------------------------------------------------------------------- */
/*      FRID PRIM values.                                               */
/* -------------------------------------------------------------------- */
#define PRIM_P          1       /* point feature */
#define PRIM_L          2       /* line feature */
#define PRIM_A          3       /* area feature */
#define PRIM_N          4       /* non-spatial feature  */


> NO.2
> 
> I got some info via ogrinfo from a s-57 file(*.000). In a caution area 
> object(CTNARE),some fields are as follows:
> 
> PRIM=3---------------------------------------------------which means the 
> object's geometry is a face, right?

Yes, it means it is an area feature.

> NAME_RCNM=130-----------------------------------which means the vector 
> record's type is edge, I guess. But the next three fields should exist 
> with a face vector record(5.1.3.3 chapter in S-57 Editon3.1 seems give 
> this hint, but I'm not sure it's true.)
> 
> ORNT=2:2,2
> USAG=2:1,1
> MASK=2:255,255

Was there a question in here?

> And another two questions:
> 
> NO.1
> 
> The field value in spatial records such as "NAME_RCID=2:25,413" has a 
> prefix "2:", does it mean the field belong to spatial record not feature 
> record?

The fields NAME_RCID and and NAME_RCNM are list fields, so the first
value is the report is the count of items in the list followed by a
colon, and then the list of values separated by commas.  It is just
a particular reporting format of the ogrinfo program.

> NO.2
> 
> And why one is 25,and another is 413?Does it mean 25 is the ID in 
> spatial record and 413 is the ID in the whole record?

It presumably means there are two edge objects one with
RCID=25 and one with RCID=413.