Line definition file format

This page describes the format of files created when you export a line. These files have an .evl extension and may be referred to as "EVL files".

You can view the exported files in an external application (this information on this page should allow you to write software to do this). You can also create or modify EVL files for import into Echoview. If you create or modify EVL files you should do so carefully as Echoview may crash or exhibit other problems on encountering a file that it considers corrupt.

Overall structure

EVL files are structured text data files. A CR/LF pair terminates each line (this is the DOS convention, not the UNIX convention that uses a single LF to terminate each line).

An EVL file consists of the following parts:

Structure of a line describing a single data point

The following fields are written for each data point. The fields are separated by spaces (any number of spaces).

Field

Description

date

CCYYMMDD

time

HHmmSSssss

depth

meters

line status

0 = none
1 = unverified
2 = bad
3 = good

Where:

CC

=

century

e.g.

20

YY

=

year

e.g.

03

MM

=

month

e.g.

01

DD

=

day

e.g.

07

HH

=

hour

e.g.

14

mm

=

minute

e.g.

23

SS

=

second

e.g.

13

hh

=

hundredths of a second

e.g.

87

ssss

=

0.1 milliseconds

e.g.

2854

Special values in .evl files

Sounder-detected bottom lines and lines based on sounder-detected bottom lines can include date and time records without an associated depth. EVL file exports include the special (depth) value -10000.99000 to signify that depth information was unavailable.

Example file

EVBD 3 3.00.41
8
20000410 1530453205  205.321984 3
20000410 1530552245  203.043990 0
20000410 1531139215  198.743539 3
20000410 1532419230  178.502529 1
20000410 1534396220  215.121401 3
20000410 1534407190  215.121401 2
20000410 1536538200  187.270428 3
20000410 1536549220  187.484544 0