Vector Formats:
Line formats do nothing more than draw lines on a map, such as coastlines or political boundaries.
The UNG format is used by ESRI software to deconstruct shapes into simple lines, usually for purposes of export. This example shows the 3rd and 4th segments of a much longer file for the national boundary of Namibia.
3
16.479476,-28.629042 16.480063,-28.629628 16.480650,-28.629628 16.481236,-28.629042 16.481236,-28.627575 16.480943,-28.626988 16.479476,-28.628455 16.479476,-28.629042
END 4
16.474489,-28.628455
16.475076,-28.628748 16.475663,-28.628748 16.476249,-28.628455 16.475956,-28.627868 16.475076,-28.627868 16.474489,-28.628455
END
The General Bathymetric Chart of the Oceans Digital Atlas has an ASCII export utility for coastlines and bathymetry contours. One option (although it is not identified as such) is BASED ON THE OLD GF3 format, developed mainly by the European marine community in the 1980's within a family of precedent-setting standards. In GF3 latitude always precedes longitude.
The BLN format is used by the Surfer gridding and contouring program to draw simple boundary lines, or to blank areas that should not have grid values or contour lines. This example is the first few lines of a 385-line segment that draws the boundary of Ethiopia. If used as a blanking file, it would blank the area inside the polygon, as indicated by the "1" in the first line; a "0" would direct blanking everything outside the same polygon.
385,1,"Ethiopia",""
36.591827,14.193720 36.579544,14.316048 36.619656,14.279283 36.658218,14.295569 36.702435,14.284711 36.735542,14.295569 36.774113,14.295569 36.829369,14.300995 36.906624,14.295569 36.950779,14.284711 36.950779,14.268429 36.978302,14.241290 37.028034,14.252145 37.088718,14.279283 37.110752,14.355270
Plotter formats are also sometimes called "List Formats" because essentially they consist of long lists of objects to draw sequentially on a map or screen.
DXF was developed by AutoCAD and is still copyrighted. It is widely used throughout the GIS community as an exchange format between systems that cannot read each other's native formats. This example is a small portion of a file that draws the 400-m depth contour offshore Namibia. DXF files are extremely confusing to "read" because they have few easily seen anchor points where you can begin reading a sequence.
0
SECTION
2
HEADER
9
$ACADVER
1
AC1006
0
ENDSEC
0
SECTION
2
TABLES
0
TABLE
2
LTYPE
70
16
0
LTYPE
2
CONTINUOUS
70
64
3
GS Solid
72
65
73
0
40
0.00116550116550052
0
LTYPE
2
GSDASHED
70
64
3
GS Internal Dash
72
65
73
2
40
1.74941724941725
49
1.16666666666667
49
-0.583916083916083
0
LTYPE
2
GSDOTTED
70
64
3
GS Internal Dot
72
65
73
2
40
0.583916083916083
49
0.00116550116550052
49
-0.583916083916083
HPGL was developed for plotters, and quickly became an industry standard. The freeware program IrfanView can apparently still convert HPGL to other formats if you have a legacy file to deal with. See the excellent example on the Wikipedia DXF page, cited below. There is a short, simple example of an HPGL file at the HPGL reference below.
Some of the above formats can be read by GIS systems, but only as ancillary or exchange data. The true GIS vector formats are these below:
The ESRI coverage format (see documentation link below) is an older format that can accomodate both vectors and rasters. Apparently it can accomodate about 15 different types of mapping concepts, corresponding exactly to the E00 compression format, also developed by ESRI. Thus coverages usualloy consist of numerous separate files when they are uncompressed. Coverages are often associated with the somewhat dated ArcInfo software versions from ESRI, and there are indications that both are slowly losing importance in the GIS field.
The VPF (see documentation link below) is a robust GIS format developed by the US military in cooperation with other national defense agencies. Although many of its products are restricted or of lesser importance to oceanographers, Vector Map (see links below) is widely used around the world. The VPF format is based on physical mapping relationships specified by very large physical layouts of files and folders.