Frequently Asked Questions

see also Hints and Tips   Special Keys and Stuff

Why can't I upload to a Garmin GPS at 115,000 BAUD, Mapsource does it.

115,000 baud can be used for uploading maps and for upgrading the ROM software in the GPS, but to the best of my knowledge and experiments it does not work for upload/download of waypoints etc, if someone can show me any software which can do it I will try to do it also.

It would be great if the map calibration points could be set using keyboard control with the arrows, the mouse is too coarse for this.

Already there, the arrow keys scroll the whole map, but the shift + arrow keys  will move the calibration point marker (bulls eyes). The method is to select the cal point required and use the mouse to place the cal marker close to the spot required, then use the shift + arrow keys to move it into place. This is mentioned in the Special Keys and Stuff help section.

Why doesn't OziExplorer have zooms larger than 750%

OziExplorer is Raster software (that is it uses images for the map, even the blank map is just an image). Zooming in on a raster image does not improve accuracy. The best a raster map can be calibrated to is +or - 1 pixel, when you zoom in at say 500% (x5 times) each pixel in the map image is increased 5 times, the accuracy of a position is now +or - 5 screen pixels. There seems little point in adding more zoom levels, as the calculations cause pixel rounding the liklehood of causing positional errors (on the zoomed screen that is) increases as the zoom level increases.

I do agree the blank map zooming could be improved as an image need not be used for that but to do that I have to rewrite quite a bit of the code and am saving that for a while.

Why can't there be unrestricted zoom levels.

The true mapping image formats such as TIFF (geotiff), BSB, NOS/GEO, maptech PCX and my own formats OZF and OZF2 are paged from disk as required, so only a small portion of the image is in memory at any time. When a zoom level is required, for example, at 50% zoom only every 2nd scanline (row) of the image is read from disk, at 33% (actually 33.333%) only every 3rd scanline is read, this speeds up image reading and therefore display times. This means only those zoom levels which can be divided into 100 evenly can be done (quickly) (50,33.33,25,20, etc). This limits the zoom levels available and the way zooming can be done. Hence there is no zooming by dragging the mouse and you are not able to enter your own zoom levels into the combo box.

Other image formats could have other zoom levels but I have decided to just use the 1 method, however I have added a 75% zoom level for other image formats.

How come a 75% zoom level is not available for TIF, BSB and OZF files.

See the explanation above.

When I load in some maps the higher level zooms (up to 750) are not available.

With large maps the large levels of zoom cause the size of the map to exceed the internal limitations of windows, this is a by-product of the method I used to implement the zoom. To avoid this problem the levels of zoom which would cause the problem have been removed.

Are there other ways of Zooming instead of having to select the Zoom combo box all the time.

The PgUp/PgDn keys zoom the map in and out.

There are 50, 100 and 200% zoom levels available on the right click map menu.

There are + - zoom buttons on the toolbar.

There will soon be a version released which has specific zoom buttons which can be added to the user toolbar, including a "Full" zoom button.

When I use the Zoom there is a considerable delay until control is returned.

This is an unavoidable problem when using very large BMP image files for the map and your system doesn't have enough memory. In this case Zoom is unusable with very large files, reduce the size of the files if possible. This problem does not occur with tiff files which use a different method for zooming. Tiff files can only be used by the registered version.

I calibrated my map but waypoints do not plot on the map when I download them from the GPS or load them from a file even though they should.

Very likely the map calibration is wrong. Make sure you have set the E/W or N/S fields to specify negative positions of latitude and longitude. Make sure the positions are in Degrees and decimal minutes. If using UTM make sure you specify the correct zone and use the N/S field to indicate if you a north or south of the equator.

All waypoint positions I download plot slightly off from where they should by the same amount, why is this.

Datums, Datums, Datums. A mismatch of datums cause this sort of affect. If you only have the shareware version and have a Lowrance or Eagle make sure the GPS has its datum set to match the Map you are using when you collect the data. Note some Lowrance and Eagles now output all data in WGS84 so check out exactly what your GPS does.

If you have a Garmin it will always download in WGS84 no matter what datum you set the GPS to so with the shareware version there is nothing you can do.

To fix this problem you must have the registered version so datums can be set for the Map and GPS. But before you set Datums read the Datums help.

When I print the map or save it as a BMP or PNG file the tracks or routes are not shown even though I have them loaded.

The tracks or routes will only be printed or saved on the map if they are visible on the screen map (not just loaded), this is a sort of "what you see is what you get" approach.

I have a track loaded and displayed on the map but when I start to use moving map the track seems to disappear even though the show tracks button is down.

The track you have displayed would be loaded into Track 1. When you start using moving map and display the Moving map Control this sets up its own parameters for Track 1, you may have it set to only display a certain number of track points as a tail from your position.

When I add the symbols to the symbols directory in OziExplorer they do not appear in the symbol selection for Waypoints.

The symbols are only for use by Map Features. The symbols used by the waypoints are fixed to match those available in your GPS and cannot be altered by the user.