Difference between revisions of "ConvertToXYZ"

Revision as of 19:11, 8 October 2010

ConvertToXYZ is a small tool that extracts baseline three-dimensional data into XYZ points files. It is useful, for instance, to extract baseline data to create bathymetries (or topography in land projects).

Quick Start

1. Map a network drive to the data file (ETOPO, GEBCO, NOAA etc...).
2. Create and edit a ConvertToXYZ.dat file. Save it in the same path of the executable.
3. Run the executable.

Options file

WARNING: Only use integer coordinate lat/lon numbers.

FILE_TYPE: is the parameter that defines the type of input data. 
It accepts values from 1 to 6 that indicates the following possible origins of data:
1 NASA SRTM (Shuttle Radar Topography Mission)
2 ETOPO 2 (every 2')
3 ETOPO 5 (every 5')
4 Shoreline (Mapgen)
5 GEBCO  (every 30" or 1')
6 ASCII  (ArcView.....)
7 NASA SRTM30 (every 30")
INPUT_FILENAME: input data file,
OUTPUT_FILENAME: where the results will be written,
TOP, BOTTOM, LEFT, RIGHT: Latitude and longitude minimum and maximum values (integers only!)
WRITE_AS_BATHYMETRY: indicates if equal to 1 that the output is written in bathymetry format

ETOPO2

Here's what the options ConvertToXYZ.dat file looks like:

<begin_window>
FILE_TYPE                   : 2
INPUT_FILENAME              : Z:\etopo2.dat
OUTPUT_FILENAME             : WestIberiaET2.xyz
TOP                         : 46
BOTTOM                      : 33
LEFT                        : -14
RIGHT                       : -5
MAXIMUM                     : 1
MINIMUM                     : -9999
WRITE_AS_BATHYMETRY         : 1
CONVERT_TO_HDF5             : 0
<end_window>

GEBCO

For GEBCO bathymetric downloaded data the file would look like:

<begin_window>
FYLE_TYPE                    : 5
INPUT_FILENAME               : 60W30S_40W10S.cdf
OUTPUT_FILENAME              : 60W30S_40W10S.xyz
MAXIMUM                      : 1
MINIMUM                      : -9999
WRITE_AS_BATHYMETRY          : 1
CONVERT_TO_HDF5              : 0
<end_window>

SRTM30

Caution: make sure the ORIGIN_X and ORIGIN_Y correspond to the BOTTOM-RIGHT origin of the srtm30 original source file! Here's a map of srtm30 tiles.

<begin_window>
FILE_TYPE                   : 7
TOP                         : 46
BOTTOM                      : 33
LEFT                        : -14
RIGHT                       : -5
MAXIMUM                     : 1
MINIMUM                     : -9999
INPUT_FILE                  : \\kepler\DataCenter1\DataCenter\DadosBase\Oceanografia\Batimetria\SRTM30\Data\w020n40.Bathmetry.srtm
XYZ_OUTPUT_FILENAME         : WestIberiaSRTM.xyz
ORIGIN_X                    : -20
ORIGIN_Y                    : -10
<end_window>

NASA Topography

1) If you have NASA binary files (.hgt):

For land topography look on \\kepler\DataCenter1\DataCenter\DadosBase\Terra\Topografia\NASA

In Eurasia folder you will find data for Europe. Copy the .zip files you need (or all) to your Hard Disk and unzip them.

Run the ConvertToXYZ with a structure adapted to your needs:

<begin_window>
FILE_TYPE             : 1
LEFT                  : -9.28
RIGHT                 : -9.056
TOP                   : 38.99
BOTTOM                : 38.75
INPUT_FOLDER          : D:\Dados\NASA\
XYZ_OUTPUT_FILENAME   : D:\Aplica\Trancao\Trancao.xyz
SAMPLE_POINTS         : 1
CONVERT_TO_UTM        : 1
<end_window>

2) If you have NASA grids (e.g. SRTM from site):

Convert DEM grid to ascii (e.g. using ArcView ->File->ExportDataSource)

Convert ascii to .xyz using MOHID GIS (->Tools->ImportArcVieAsciiGrid). Select .xyz format and choose the filename and location.

See also

• Digital Terrain Creator