Lab II Section I: Point Database Conversions
- Manual Conversions
Objective:
Use the interactive spreadsheet (Point Database
Conversions) to convert a list of coordinates from Geodetic Lat/Long to
Universal Transverse Mercator.
The Point
Database Conversion function of the Geographic Calculator is designed
to handle coordinate conversions on columns of data in a table. This exercise
will familiarize the user with the basic workings of the Point Database
Conversion area.
For this
excercise, you have been given an Excel spreadsheet containing coordinates.
The coordinates are in Geodetic Lat/Long, WGS84. They must be converted
to Universal Transverse Mercator grid values.
Follow these steps to complete a conversion
of these coordinates in a Point Database Conversions job:
Open
the Geographic Calculator.
Click
on the Point Database Conversions
job to open the interface.
Load
a point database file by clicking the Load Data button below the grid
table on the left.
On the dialog that opens, select the radio button Use File, and click
the Browse button to locate the file you will open. The
file to open is in teh folder for the Getting Started Guide (C:\Program
Files\Blue Marble Geo\Geographic Calculator 7.0\Getting Started Guide)
named Input_coordinates.xls.
When
you open the file, you will be asked if the file contains a Header. Select
Yes. This
will use the first row of the spreadsheet to name the columns in the table.
Once
loaded, the table should look like this:
To
select your Input Coordinate System
, double-click on the blue box labeled System in the right-hand Coordinate
System area at the bottom of the job page. By
default, the Calculator starts with the geodetic coordinate system of
WGS84 selected. This
will launch the Select Coordinate System dialog:
In
the Select Coordinate System dialog, coordinate systems are organized
in the folder list on the left by type (Geodetic Lat/Long, Projected,
Geocentric, and Fitted), continent, then by country. In
the tree view on the left, browse under Geodetic>World,
in the coordinate system list on the right, select WGS84
Coordinate System.
Select
the format for your input point by going to the Coordinate
System area and clicking on the Format
control button.
-
A dialog box
will appear. Select
the following parameter:
|
Input Format: |
DD MM SS.
(All other information
on this page controls the output display) |
Leave
the Vertical Reference field, set to (none).
There are no elevation parameters for this conversion.
To
select the output coordinate system, double-click on the blue box labeled
System in the Coordinate System area at the bottom right of Point Database
job. By
default, the Calculator starts with the geodetic coordinate system of
WGS84 selected. This
will launch the Select Coordinate System dialog.
To
select the Universal Transverse Mercator Zone 19 North, in the tree view
on the left, browse under Projected>UTM>WGS84,
in the coordinate system list on the right, select Zone
19N. Then
click OK.
Select
the format for your output point by going to the Coordinate
System area and clicking on the Format
control button.
-
A dialog box
will appear. Select
the following parameter:
|
Decimal
Precision: |
2
|
In
this example, both the input and output coordinate systems use WGS84 as
the datum, so a Datum Transformation is not necessary.
Now that
the source and destination coordinate systems have been defined you can
set up your Conversion Settings.
Initialise
the Conversion Settings
for your conversion by clicking on the Conversion
Settings control
button.
On
the Input side of the Conversion
settings dialog set the drop down menus to match the column headers for
the latitude and longitude columns.
On
the Output side of the settings,
use the Add buttons to create
a new column for the Northing,
and a new column for the Easting.
The conversion settings dialog, should then look like this:
Click
OK, to accept the column settings.
Click
on the Calculate button. The UTM
coordinates will appear in the columns you created via the Conversion
Settings dialog.
Below are
the sample results that should be displayed:
