CSV File Conventions

CSV files are text files and typically have the extension .txt, .dat or .csv . Each line in the file corresponds to a single vertex point of the geometric shape which is defined by the geographic coordinates as a mandatory file content. These coordinates must be stored in distinct columns (see below) separated by the 'tabulator' character (the 'semicolon' character in the special case of MERMAID extraction files, see here). A CSV file must have a header line as described below in order to specify column names (the only exception are SeaDAS 6.x track files which are another special case of CSV files, see here).

Formal Description of a valid CSV File

The formal description of a CSV File which SNAP will regard as 'valid' looks as follows:

        feature-format         := {<property-record> NL} <feature-type-record> {NL <feature-record>}
        feature-type-record    := {<feature-type-name>} {<sep> <attribute-header>}
        feature-record         := {<feature-id>}           {<sep> <attribute-value>}

        simple-format          := {<property-record> NL} <header-record>       {NL <data-record>}
        header-record          := <attribute-header> { <sep> <attribute-header>}
        data-record            := <attribute-value>  {<sep> <attribute-value>}

        attribute-header       := <attribute-name> [<attribute-type-spec>]
        attribute-type-spec    := ':'<attribute-type>
        property-record        := '#'<property-name> '=' <property-value>
        sep                    := TAB | [';' | ',', ...]  (TBC)

Comment Lines

The CSV dataset may contain introductory comment lines at the beginning of the file. These lines must start with a '#'.

Header Line

The header line follows after the last comment line. It contains column names which are also expected to be separated by the 'tabulator' character. Optionally, the name can be given together with a corresponding data type, which must be separated from the name by a ':'.

For a spatial interpretation of the given data, the CSV data must contain geo-information given as

Latitude/Longitude: Column name (converted to lower case) must be either 'lat' or 'latitude' in case of Latitude, and either 'lon', 'long' or 'longitude' in case of Longitude.
Geometry: As additional option, the Sentinel Toolbox supports geoinformation given as geometries which are conform with the Simple Features Specification published by the Open GIS Consortium. These are in particular point (Point), line (LineString) and area (Polygon) as well as their corresponding multi-variants (MultiPoint, MultiLineString, MultiPolygon).

Consequently, a valid column header would be one of {'geometry:Point', 'geometry:LineString', 'geometry:Polygon', 'geometry:MultiPoint', 'geometry:MultiLineString', 'geometry:MultiPolygon'}.
In addition, the first data column must contain a unique ID for the geometries (e.g. an index 0, 1, 2,...), and the header of the first column must be one of {'org.esa.snap.Point', 'org.esa.snap.LineString', 'org.esa.snap.Polygon', 'org.esa.snap.MultiPoint', 'org.esa.snap.MultiLineString', 'org.esa.snap.MultiPolygon'}.

If the CSV data set does not provide valid geoinformation as described above, the data set will be rejected as invalid.

Record Lines

The record lines follow after the header line. Each line contains a record with data values as specified by the column names and data types given in the header. All data values are also expected to be separated by the 'tabulator' character. The data types are either interpreted automatically or, if given, taken from the column data types in the header line.

If a column named 'Label' or 'label' is present in the CSV data, the corresponding entries will be drawn as label in the current view of the Sentinel Toolbox.

Examples for valid CSV Files

SNAP pin export table

        # SNAP pin export table
        #
        # Product:      subset_0_of_MER_RR__1PNPDK20030813_094018_000022742019_00022_07591_4499
        # Created on:   Thu Apr 26 11:14:57 CEST 2012

        Name    X       Y       Lon             Lat             Label   Desc
        pin_1   215.5   110.5   9.943068        43.09783        Pin 1   first
        pin_2   257.5   111.5   10.458842       42.990147       Pin 2   second
        pin_3   273.5   139.5   10.553919       42.664112       Pin 3   third
        pin_4   259.5   161.5   10.302726       42.470406       Pin 4   fourth
        pin_5   220.5   157.5   9.838505        42.601866       Pin 5   fifth
        pin_6   199.5   135.5   9.656987        42.87649        Pin 6   sixth
        pin_7   215.5   110.5   9.943068        43.09783        Pin 7   seventh

Internal SNAP pin CSV file

        #defaultCSS=symbol:pin; fill:#0000ff; fill-opacity:0.7; stroke:#ffffff; stroke-opacity:1.0; stroke-width:0.5
        org.esa.snap.Pin        geometry:Point  style_css:String        label:String    text:String     pixelPos:Point  geoPos:Point    dateTime:Date
        pin_1   POINT (3.011064291000366 43.2885627746582)      [null]  Pin 1           POINT (476.5 658.5)     POINT (3.011064291000366 43.2885627746582)      [null]
        pin_5   POINT (6.4610161781311035 45.858734130859375)   [null]  Pin 5           POINT (660.5 365.5)     POINT (6.4610161781311035 45.858734130859375)   [null]
        pin_2   POINT (3.9401633739471436 42.58957290649414)    [null]  Pin 2           POINT (565.5 706.5)     POINT (3.9401633739471436 42.58957290649414)    [null]
        pin_3   POINT (4.629702568054199 41.38515853881836)     [null]  Pin 3           POINT (651.5 803.5)     POINT (4.629702568054199 41.38515853881836)     [null]
        pin_4   POINT (3.0791780948638916 40.82112121582031)    [null]  Pin 4           POINT (545.5 882.5)     POINT (3.0791780948638916 40.82112121582031)    [null]

Two Multipolygons

        # MULTIPOLYGONs
        #
        # Product:      subset_1_MER_RR__1PQBCM20030809_101416_000002002018_00466_07534_0168
        # Created on:   Thu Apr 12 14:48:36 CEST 2012

        # Wavelength:                                                   884.94403
        org.esa.snap.Multipolygon       Name:String     Geometry:MultiPolygon   radiance_14:Double
        0       multipolygon_1  MULTIPOLYGON (((10 47, 0 43, 6 40, 10 47)), ((2 39, 3 39, 2.5 38, 2 39)))       59.383057
        1       multipolygon_2  MULTIPOLYGON (((8 38, 2 45, 8 42, 8 38)), ((3 35, 5 36, 3.5 39, 3 35))) 59.383057