Resolving Data Positioning in Oasis montaj

The second major step in the Oasis montaj data processing sequence is to resolve data positioning. This process can consist of interpolating, projecting and/or warping data.

Introduction to Coordinate Systems and Projections

A coordinate system defines how geographic locations on Earth (longitude and latitude in some datum) are represented on a flat map sheet. Geographic map locations (X, Y, Lat, Long) are either in an implied or a known coordinate system. If you do not specify a coordinate system for your data, Oasis montaj will assume it is unknown.

Define map coordinate systems if you want to do the following:

• Annotate maps with longitude, latitude locations

• Convert the location of information (data or grids) from one coordinate system to another

• Display information on a map that is in a different coordinate system

• Define a warped coordinate system to fit data to a desired map coordinate system

In Oasis montaj, working with coordinate systems requires that the map coordinate system information is attached (i.e. *.GI file) to the data. Once you have attached a coordinate system to a set of coordinates, Oasis montaj will perform any reprojection necessary to properly display the data with another dataset of a different coordinate system on a map.

Oasis montaj features "smart projections", which enables the system to project data "on the fly" as it is displayed. This ability enables maps to have several views, each containing different coordinate systems. In addition, dynamic links between maps and data are maintained even if different coordinate systems are used.

Map projections can be defined for any pair of channels in a database, for a grid coordinate system, and for a data view in a map. In most cases, all that is required is to define the coordinate system of the "X" and "Y" channels of an original database. This coordinate system will then be passed on to grids when data is gridded, and map views will inherit this projection when they are created and posted to the map. Coordinate systems for data channels, grids and views can also be viewed and modified at any time; although, the modification of map coordinate systems does require specific and accurate knowledge of the coordinate system information.

What do you want to do?

Interpolate Data

Define and Modify Map Projections

Define the coordinate system for database channels

Define the coordinate system of a grid

Define the coordinate system of a map view

Annotate Longitude and Latitude Coordinates on a Map

Display with Different Coordinate Systems on a Map

Define and Apply a Warp

Warp Data and Grids

Define a warp file interactively

Define a warp file semi-interactively

Apply a Warp to a Grid

Apply a Warp to an Image

Apply a Warp to Data

Attach a Warp to a Grid