How to access Shapefile metadata and metatypes information using OGR?

Question

I'm trying to use ogrinfo to get some details on a shapefile. Now, the only way that I know is using orginfo:

ogrinfo -ro -so -al  BRA_001.shp

But its display all information about the shape:

INFO: Open of `.\BRA_001.shp'
      using driver `ESRI Shapefile' successful.

Layer name: BRA_001
Geometry: 3D Polygon
Feature Count: 273
Extent: (-42.645514, -22.360532) - (-42.321728, -22.198300)
Layer SRS WKT:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        TOWGS84[0,0,0,0,0,0,0],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.0174532925199433,
        AUTHORITY["EPSG","9108"]],
    AUTHORITY["EPSG","4326"]]
Name: String (0.0)
description: String (0.0)
timestamp: String (0.0)
begin: String (0.0)
end: String (0.0)
altitudeMode: String (0.0)
tessellate: Integer (0.0)
extrude: Integer (0.0)
visibility: Integer (0.0)
drawOrder: String (0.0)
icon: String (0.0)

It's very useful by the way, but what I need is get only metadata names with types, e.g.:

Name: String (0.0)
description: String (0.0)
timestamp: String (0.0)
begin: String (0.0)
end: String (0.0)
altitudeMode: String (0.0)
tessellate: Integer (0.0)
extrude: Integer (0.0)
visibility: Integer (0.0)
drawOrder: String (0.0)
icon: String (0.0)

Can someone help me out?

Answer 1

A very quick way would be to use the linux command line utility tail as follows:

ogrinfo -ro -so -al  BRA_001.shp | tail -n + 20 

However, this won't always be reprocible if the SRS is different. As user30184 mentioned, you would need to use the OGR API. The following example is in Python:

from osgeo import ogr
shpFile = r"./BRA_001.shp"

dataSource = ogr.Open(shpFile)
layer = dataSource.GetLayer(0)
layerDefn = layer.GetLayerDefn()

for i in range(layerDefn.GetFieldCount()):
    fieldName = layerDefn.GetFieldDefn(i).GetName()
    fieldTypeCode = layerDefn.GetFieldDefn(i).GetType()
    fieldType = layerDefn.GetFieldDefn(i).GetFieldTypeName(fieldTypeCode)
    fieldWidth =  layerDefn.GetFieldDefn(i).GetPrecision()

    print str(fieldName) + ": " + str(fieldType) + " (" + str(fieldWidth) + ")"

Here is an example that prints the output as a JSON Array:

import sys
try:
    from osgeo import ogr, gdal
except:
    sys.exit('[ ERROR ]: cannot find GDAL/OGR modules')



def printMetadata(daShapefile):
    dataSource = ogr.Open(daShapefile)
    daLayer  = dataSource.GetLayer(0)
    layerDefinition = daLayer.GetLayerDefn()

    c = layerDefinition.GetFieldCount()
        print "["
    for i in range(c):
        fieldName =  layerDefinition.GetFieldDefn(i).GetName()
        fieldTypeCode = layerDefinition.GetFieldDefn(i).GetType()
        fieldType = layerDefinition.GetFieldDefn(i).GetFieldTypeName(fieldTypeCode)
        fieldWidth = layerDefinition.GetFieldDefn(i).GetWidth()
        GetPrecision = layerDefinition.GetFieldDefn(i).GetPrecision()

        if((c - 1) != i):
            scape  = ','
        else:
            scape  = ""

        print("{\"name\":\"%s\",\"type\":\"%s\",\"length\":%s,\"precision\":%s}%s" % (fieldName,fieldType,str(fieldWidth),str(GetPrecision),scape))

    print "]"

if len( sys.argv ) < 2:
    sys.exit('[ ERROR ]: You must define a file ')
else:
    file_path_name = sys.argv[1]
    printMetadata(sys.argv[1])

Answer 2

If you want to stay in the command line here is an example using the OGR wrapper fiona and the JSON parser jq.

>fio info BRA_001.shp | jq '.["schema"]["properties"]'
>
{
"Name": "str:0"
"description": "str:0"
"timestamp": "str:0"
"begin": "str:0"
"end": "str:0"
"altitudeMode": "str:0"
"tessellate": "int:0"
"extrude": "int:0"
"visibility": "int:0"
"drawOrder": "str:0"
"icon": "str:0"
}

fio info returns a JSON of the ogrinfo output. This is easier and more reliable to parse than pure text output. With jq you just select the information you want to see - the properties in your case.