Use this procedure to get general information about an EVF. After you open the EVF with ENVI_EVF_OPEN (or ENVI_EVF_DEFINE_CLOSE returns the EVF ID), use the appropriate keyword to retrieve the number of records, layer name, data type, or projection.
Syntax
ENVI_EVF_INFO, EVF_ID [, DATA_TYPE=variable] [, LAYER_NAME=string] [, NUM_RECS=variable] [, PROJECTION=structure]
Arguments
EVF_ID
This is the EVF ID returned from ENVI_EVF_OPEN or ENVI_EVF_DEFINE_CLOSE.
Keywords
DATA_TYPE (optional)
Use this keyword to specify a named variable that contains the ENVI Classic data type of the vector file. DATA_TYPE uses the following IDL convention.
- 1: Byte (8 bits)
- 2: Integer (16 bits)
- 3: Long integer (32 bits)
- 4: Floating-point (32 bits)
- 5: Double-precision floating-point (64 bits)
- 6: Complex (2x32 bits)
- 9: Double-precision complex (2x64 bits)
- 12: Unsigned integer (16 bits)
- 13: Unsigned long integer (32 bits)
- 14: Long 64-bit integer
- 15: Unsigned long 64-bit integer
LAYER_NAME (optional)
Use this keyword to specify a named variable that contains the string name for the EVF layer. Each EVF consists of only a single layer.
NUM_RECS (optional)
Use this keyword to specify a named variable that contains the number of vector records in the EVF.
PROJECTION (optional)
Use this keyword to specify a map projection. PROJECTION is a projection structure returned from ENVI_GET_PROJECTION or ENVI_PROJ_CREATE. The default projection is Arbitrary.
Example
See the code example under ENVI_EVF_CLOSE.
API Version
4.2