Support Files : Coordinate Reference Systems : Map Definition File
 

Map Definition File

The map definition file (mapdef.dat) contains a list of CRSs.

The file is located in C:\Program Files\CARIS\Caris\<version>\
system).

Do not edit this file. Create a copy and use the copy for custom map definitions.

Sample entries from the map definition file are shown below:

[UTM - NAD83]

UTM-24N-Nad83,"Zone 24N (42 W TO 36 W)",NEMR,NA83,UM,0,0,0,500000,0.9996,0,-39,0

UTM-25N-Nad83,"Zone 25N (36 W TO 30 W)",NEMR,NA83,UM,0,0,0,500000,0.9996,0,-33,0

UTM-26N-Nad83,"Zone 26N (30 W TO 24 W)",NEMR,NA83,UM,0,0,0,500000,0.9996,0,-27,0

UTM-27N-Nad83,"Zone 27N (24 W TO 18 W)",NEMR,NA83,UM,0,0,0,500000,0.9996,0,-21,0

Lines that start with # are comments.

Map definition entries are collected in groups. The group name, enclosed in square brackets, is on a line by itself, followed by an unlimited number of definitions, one per row. Each definition can be no longer than 400 characters.

Definition fields are separated by commas. The first five fields are required. The remaining fields (the numeric fields) depend on the CRS and projection. If a numeric field is not required, enter a value of 0. You cannot omit a field.

Each definition line has the following format:

Field

Type

Maximum

Description

Example

Key

Char

20 characters

The map definition key. Must be unique.

UTM-24N-Nad83

Description

Char

80 characters

A description for the definition.

Must be enclosed in double quotes. Must contain no commas.

"Zone 24N (42 W TO 36 W)"

Coordinate system

Char

4 characters

NEMR, NRMR, LLDG or CHMR (see table below)

NEMR

Ellipsoid

Char

4 characters

From the datum file. See Datum File

NA83

Projection

Char

4 characters

Projection code. See the list below.

UM

Scaling latitude 1

Real

10 dec. places

The latitude of the geographic origin.

0

Scaling latitude 2

Real

10 dec. places

The latitude of the geographic origin

0

False North

Real

10 dec. places

An offset applied to all northings.

0

False East

Real

10 dec. places

An offset applied to all eastings.

500000

Scaling factor

Real

10 dec. places

The amount of distortion to be expected at the geographic origin.

0.9996

Latitude origin

Real

10 dec. places

The latitude of the geographic origin.

0

CMorLO

Real

10 dec. places

Central meridian or longitude origin, depending on the projection.

-39

Skew azimuth

Real

10 dec. places

The azimuth of a great circle, in degrees east of north, which passes through a point of origin.

0

CARIS uses four horizontal coordinate systems:

Coordinate System

Description

NEMR

The coordinates are expressed as Northings and Eastings of a projection in metres on the ground (hence Northings and Eastings in MetRes).

NEMR is a projected coordinate system. Projected systems, such as Universal Transverse Mercator (UTM), Stereographic, or Mercator provide their own mechanisms to project maps of the earth's surface onto a two-dimensional Cartesian coordinate plane.

NRMR

Coordinates expressed in metres on the map have no reference to a specific location on the ground (hence Non Registered, MetRes).

This type of coordinate system is used when the information necessary for relating the map to the real world (control points) is not necessary or not available.

LLDG

Coordinates are expressed in latitude and longitude in decimal degrees on a reference ellipsoid (hence Latitude and Longitude in Decimal deGrees).

CHMR

Coordinates are expressed in metres at the chart scale (hence CHart in MetRes). This coordinate system is used primarily for hydrographic charting.

A CHMR CRS contains a projected CRS as well as an affine transformation which relates projected coordinates to paper space. CHMR, NEMR and LLDG CRSs all provide a framework for defining real-world locations.

Valid CARIS projections:

Projection

EPSG Projection Definition

Code

Alaska Zone 11

A1 OBLIQUE MERCATOR VARIANT A ("EPSG", "9812")

A1

Azimuthal

AZIMUTHAL EQUIDISTANT ("EPSG", "9832")

AZ

Cassini

CASSINI SOLDNER ("EPSG", "9806")

CA

Gnomonic

OBLIQUE AND_EQUATORIAL STEREOGRAPHIC ("EPSG", "9809")

GN

Google Mercator

PSEUDO MERCATOR ("EPSG", "1024")

GM

Hotine Oblique Mercator A

OBLIQUE MERCATOR VARIANT A ("EPSG", "9812")

HB

Hotine Oblique Mercator B

OBLIQUE MERCATOR VARIANT B ("EPSG", "9815")

OM

Lambert Conformal Conic

LAMBERT CONIC CONFORMAL_2SP ("EPSG", "9802")

LC

Mercator A

MERCATOR VARIANT A ("EPSG", "9804")

ME

Mercator B

MERCATOR VARIANT B ("EPSG", "9805")

MR

Polyconic

AMERICAN POLYCONIC ( "EPSG", "9818")

PO

Polar Stereographic

POLAR STEREOGRAPHIC VARIANT A ("EPSG", "9810")

PS

Rectified Skew Orthomorphic

No EPSG reference

RS

Stereographic

OBLIQUE AND EQUATORIAL STEREOGRAPHIC ("EPSG", "9809")

ST

Transverse Mercator

TRANSVERSE MERCATOR ("EPSG", "9807")

TM

Universal Transverse Mercator

TRANSVERSE MERCATOR ("EPSG", "9807")

UM

1 A1 is a special projection with all hard-coded values


When creating a new entry, the numeric fields you have to consider depend upon the coordinate system and projection.

Fields

Projections

CA

GN

HB

LC

ME

PO

PS

RS

ST

TM

UM

Scaling lat 1

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

 

CHMR

Scaling lat 2

 

 

 

NEMR

CHMR

NEMR

 

 

 

 

 

 

False northing

NEMR

NEMR

NEMR

NEMR

NEMR

 

NEMR

NEMR

NEMR

NEMR

 

False easting

NEMR

NEMR

NEMR

NEMR

NEMR

 

NEMR

NEMR

NEMR

NEMR

 

Scaling factor

NEMR

CHMR

NEMR

NEMR

NEMR

CHMR

 

 

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

 

Central meridian/longitude origin

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

NEMR

CHMR

CHMR

Skew azimuth

 

 

 

 

 

 

 

NEMR

CHMR

 

 

 

Fields that contain a marker may require a value, depending on the definition. If it turns out that a particular field is not required, it should contain a 0 in the map definition entry.

NEMR

In a NEMR coordinate system, the coordinates are expressed as Northings and Eastings of a projection in metres on the ground. Distances and bearings can be carried across adjacent map sheets with this coordinate system.

This table shows which fields you may require for a map definition using a NEMR coordinate system. Any field with no marker is not required and should contain a 0.

Field

Projection

A1

AZ

CA

GN

HB

LC

ME

P0

PS

RS

ST

TM

UM

Scaling latitude 1

*

l

l

l

l

l

l

l

l

l

l

Scaling latitude 2

 

l

l

False northing

l

l

l

l

l

l

l

l

l

False easting

l

l

l

l

l

l

l

l

l

Scaling factor

l

l

l

l

l

l

l

l

Latitude origin

*

Central meridian/longitude origin

l

l

l

l

l

l

l

l

l

l

Skew azimuth

l

* For the A1 projection, you must include the same value in both scaling latitude 1 and latitude origin.

LLDG

In an LLDG coordinate system, coordinates are expressed in latitude and longitude in decimal degrees on a reference ellipsoid.

This table shows which fields you may require for a map definition using an LLDG coordinate system.

Field

Projection

A1

AZ

CA

GK

GN

HB

LC

ME

P0

PS

RS

ST

TM

UM

Scaling latitude 1

 

Scaling latitude 2

 

False northing

 

False easting

 

Scaling factor

 

Latitude origin

 

l

l

l

l

l

l

l

l

l

l

l

l

Central meridian/longitude origin

 

l

l

l

l

l

l

l

l

l

l

l

l

Skew azimuth

 

CHMR

In a CHMR coordinate system, Coordinates are expressed in metres at the chart scale. All distances and bearings are relative to that chart.

This table shows which fields you may require for a map definition using a CHMR coordinate system.

Field

Projection

AZ

CA

GN

HB

LC

ME

P0

PS

RS

ST

TM

UM

Scaling lat 1

 

l

l

l

l

l

l

l

l

l

l

l

Scaling lat 2

 

l

False northing

 

False easting

 

Scaling factor

 

l

l

l

l

l

l

l

Latitude origin

 

Central meridian/longitude origin

 

l

l

l

l

l

l

l

l

l

l

l

Skew azimuth

 

l

l