[postgis-users] Re: USGS NHD data to PostGIS

[Randy George]

Hello Ragi,

 

            Thanks for the information on shape type 19. I checked some NHD
geodatabase shape fields for a PolygonZ type 15, which has both the M and Z
values.  However, these type 19 shape fields correspond more closely to
PolygonM type 25. There appear to be additional Mmin, Mmax, and Marray[] for
each Polygon record, all of which are 0.0 for the NHD data sets I checked. I
can't really tell if the additional values are measure or elevation.

 

            Forcing to type 25 PolygonM gives correct 2D <path> geometries
but unfortunately ogr2ogr does not appear to recognize a shape type 19 or
have a way to override to 2D Polygon.

 

            In addition there appears to be a shape type 9 in NHD
HYDRO_NET_Junctions, which seems to correspond to PointM shape type 21?
Again ogr2ogr seems to skip this geometry.

 

            Does anyone know where documentation can be found for these
newer ESRI shape types?

 

Thanks

Randy

 

  _____  

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Ragi Y.
Burhum
Sent: Tuesday, February 06, 2007 4:47 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Re: USGS NHD data to PostGIS

 

 

On 2/6/07, postgis-users-request at postgis.refractions.net <
<mailto:postgis-users-request at postgis.refractions.net>
postgis-users-request at postgis.refractions.net> wrote:


Message: 8
Date: Mon, 5 Feb 2007 17:42:57 -0700 
From: "Randy George" <rkgeorge at cadmaps.com>
Subject: RE: [postgis-users] Re: USGS NHD data to PostGIS
To: "'PostGIS Users Discussion'"
        <postgis-users at postgis.refractions.net>
Message-ID: <20070206004258.B982162D448 at mpls-qmqp-05.inet.qwest.net >
Content-Type: text/plain;       charset="US-ASCII"

Hi,

        I've investigated my NHD data problem a little further. Looking at
the NHDArea table of the mdb it appears that the Shape field's internal 
'Shape Type' is listed as 19. Unless there has been a recent change, I don't
think the shp format has a type 19.

I ran a test conversion to svg forcing .shp type 19 to a type 5 (Polygon)
and I get valid polygon <paths>? 

Has ESRI added an additional "Shape Type" to the list? Or is there some
issue with NHD geodatabases?

If 19 is unknown to the ogr translator that would explain the empty geometry
columns and sporadic empty geometry fields. It would also explain why there 
is no error since those records would simply be created with no geometry.

http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
Value Shape Type 
0 Null Shape
1 Point
3 PolyLine
5 Polygon
8 MultiPoint
11 PointZ
13 PolyLineZ
15 PolygonZ
18 MultiPointZ
21 PointM
23 PolyLineM
25 PolygonM
28 MultiPointM
31 MultiPatch


Thanks
Randy


19 is a polygon with M and Z values.

Regards,

Ragi Yaser Burhum

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