GAMMA Interferometric Point Target Analysis Software (IPTA): Reference Manual

data2pt

ANSI-C program: data2pt.c

NAME
data2pt - raster to vector format conversion (extract values from a 2-D data file at specified point locations)

SYNOPSIS
data2pt <f_in> <par_in> <plist> <SLC_par> <pdata> <rec_num> <type>

<f_in>	(input) 2-D image data file (various types supported)
<par_in>	(input) SLC/MLI parameter file of 2-D image data file
<plist>	(input) point list for sampling (int)
<SLC_par>	(input) SLC parameter file of point list coordinates
<pdata>	(output) point data stack (same type as f_in)
<rec_num>	record number in output point data stack (starting with 1)
<type>	data type (0:fcomplex 1:scomplex 2:float 3:int 4:short 5:byte 6:SUN/BMP raster)

EXAMPLE
data2pt 08560.rslc 20491.rslc.par testsite.plist 20491.rslc.par testsite.pslc 4 1

Extracts complex SLC values (scomplex) at the point list (testsite.plist) coordinates from the registered SLC 08560.rslc and writes the values as record number 4 to the output point data stack testsite.pslc (scomplex). The geometry of the registered SLC is defined by the SLC parameter file, which is identical to the SLC parameter file for the point list coordinates.

data2pt ave20.rmli 20491.rmli.par testsite.plist 20491.rslc.par testsite.ave20.pmli 1 2

Extracts values (float) at the point list (testsite.plist) coordinates from the averaged backscatter intensity image (ave20.rmli) and writes the values as record number 1 to the output data stack testsite.ave20.pmli (float), a stack with just a single record. The geometry of the real valued image ave20.rmli is defined by the MLI parameter file, 20491.rmli.par, which resulted from the SLC parameter file for the point list coordinates (20491.rslc.par) by multi-looking.

INSTALLATION
Source code data2pt.c in ./IPTA/src, executable version data2pt in ./IPTA/bin

DESCRIPTION
The use of point data stacks is an important element of the IPTA. Registered SLC data and interferometric data products at the selected points are stored in such point data stacks with each record corresponding to an SLC image or an interferogram pair. Other image data, such as for example a height map, sampled at the point list coordinates, is stored in a corresponding stack but with just a single record.

data2pt supports the conversion of image data from the "normal" 2-D raster image format to the IPTA vector data format.

For the input image (in the "normal" 2-D raster image format) the geometry is specified in a SLC/MLI parameter file. The geometry of the input image can be different from the geometry of the point list coordinates which is defined in a separate SLC parameter file.

The input image can either be in the SLC geometry used for the point list coordinates or in a multi-looked geometry (relative to the same SLC geometry, without offsets in range and azimuth).

data2pt extracts values at the pixel which is the nearest neighbor to the point list coordinate (int) indicated in the point list.

The extracted values (in binary vector data format) are written to the point data stack at the indicated record number. The record numbers start with 1. The number of records corresponds to the highest record number. Stacks with just a single record are used in the case of data files as the terrain height.

If a new stack name is indicated the stack is created. Indicating a record number larger than the highest record number of the indicated stack results in an increase of the stack size.

Different data types (fcomplex, scomplex, float, int, short, byte, SUN/BMP raster) are supported. The data type of the input 2-D data and the output point data stack are assumed to be identical.

When generating an SLC stack a corresponding stack with the SLC parameters should be generated using the IPTA program SLC_par_pt.

One of the supported data types is SUN/BMP raster. This type is mainly used in the generation of data stacks of masks values (uchar). To generate a record in a data stacks of masks values a SUN rasterfile (8-bit or 24bit) can be generated and displayed. Classification or image tools (e.g. XV) can then be used to set the area to be masked out (=ignored) to black (0,0,0). Such a SUN/BMP rasterfile with black areas can then be written to the selected record of the data stack of mask values. The unsigned character written to the data stack of mask values corresponds to the grey value (= (red value + green value + blue value)/3 ) of the 8-bit or 24-bit input SUN/BMP rasterfile.

OPTIONS
none.

SEE ALSO
xpt_slc, SLC_par_pt, SLC_par, typedef_ISP.h, ipta.h.