Making your own "blank map" for your region.
Example : You may have a farm and want to use your GPS to record waypoints and tracks to position fences, paddocks, dams etc on a map. Depending on the size of the farm you may not be able to find a suitable scale map to load into OziExplorer to enable you to plot these features. (Note: the accuracy of a GPS is + or - 5 to 10 metres)
You can make your own blank map by using known coordinates that represent diagonal corners to cover the region you require. (You may be able to use the Blank Map option on the Map Menu in OziExplorer, but it has limitations - see the OziExplorer Help File for more information on the limitations).
Use any image utility program, (for the purpose of this instruction sheet we will use Microsoft Paint, which everyone who operates Windows will find under START, PROGRAMS, ACCESSORIES)
We are going to make a blank image 2000 x 2000 pixels.
Run Microsoft Paint:
Select IMAGE on the Menu
Select ATTRIBUTES and enter -
WIDTH - 2000, HEIGHT - 2000
UNITS - pixels
Select FILE on the Menu
SAVE - Save In: choose or create a folder where the image will be saved
FILE NAME - name the image eg. "blankmap"
SAVE AS TYPE - chose an image format eg. 24-bit Bitmap (*.bmp*) (Note: The Shareware Demo version of OziExplorer can only load .bmp images. The Trial version can load most image formats. Of course, if OziExplorer is registered (purchased) any of the supported formats can be used.)
Close Microsoft Paint
Select LOAD AND CALIBRATE MAP IMAGE on the FILE Menu
Find the folder and load the "blankmap.bmp", we are now going to calibrate the blank image.
The Calibration information dialog is on the right hand side of the screen.
On the SETUP Tab
Enter the Map Name to match the name of your blank image eg. Blank Map
Select the Map Datum - It must be set to the datum of the calibration points you will be entering. eg: WGS 84
Select the Map Projection - Latitude/Longitude
Now you need to enter two (2) calibration points (Point1 and Point2). These points will be diagonally opposite and must cover your area of interest. In this case the blank image created is 2000x2000, an aspect ration of 1:1, so the difference in the latitudes of the calibration points must be the same as the difference in the longitudes of the calibration points also a ratio of 1:1.
Example 1 (in the Southern Hemisphere) -
POINT 1 (top left corner of blank map) - Latitude -27˚ 30' and Longitude 152˚ 30'
POINT 2 (bottom right corner of blank map) - Latitude -27˚ 32' and Longitude 152˚ 32'
In this case the blank image created is 2000x2000, an aspect ratio of 1:1, so the difference in the latitudes (2') must be the same as the difference in the longitudes (2') also a ratio of 1:1. You could make the difference of both the Latitude and Longitude 2' or 1˚ (or whatever you want to suit the scale you want for the blank map.
Example 2 (in the Northern Hemisphere) -
POINT 1 (top left corner of blank map) - Latitude 52˚ 35' and Longitude 118˚ 20'
2 (bottom right corner of blank map) - Latitude 52˚ 33' and
Longitude 118˚ 18'
enter the points :
Click the POINT 1 Tab
Enter the image coordinates of the very upper left corner (0,0) and enter the Lat/Long coordinates for that corner. Also select the N/S and E/W for the coordinates. (In the Example 1 above, enter "S" and "E") (In the Example 2 above, enter "N" and "W")
the POINT 2 Tab
Enter the image coordinates of the very lower right corner (1999,1999) and enter the Lat/Long coordinates for that corner. Also select the N/S and E/W for the coordinates.
Click the SAVE button to save the .map calibration file for your blank map.
You now have a map which spans the coordinates which you have chosen for your calibration points.