GPSy 3.0 supports the use of user-scanned maps as well as calibrated GeoTIFF images (such as those on the USGS topo map CD-ROMs). See:
http://www.gpsy.com/maps/
for sources of GeoTIFF format maps, including USGS DRG Topo Maps and Digital Orthophoto Maps.
Scanned map support requires QuickTime 2.5 or above to be installed. QuickTime 3.0 is recommended for TIFF support, GeoTIFF auto-calibration support and full compatibility:
http://quicktime.apple.com
GeoTIFF Images
GPSy 3.0 supports GeoTIFF tagged USGS CD-ROM Digital Raster Graphs (aka USGS Topo maps on CD-ROM). GPSy will recognize the GeoTIFF tags and auto-calibrate the map. Be sure to match your primary display datum to the one that the map uses (usually located on in the map README or border of the map).
Please read the notes on scanned images below to see how to get maximum resolution on your images. Basically, give GPSy as much memory as you can.
GeoTIFF support requires QuickTime 3.0 to be installed: http://www.apple.com/quicktime/
For a list of CD-ROMs available in GeoTIFF format, see: http://www.gpsy.com/maps.html
If you come across any GeoTIFF images that open with "Unrecognized GeoTIFF Tags" in GPSy, please contact technical support <support@gpsy.com>. We welcome such input as we want to have robust GeoTIFF support.
Calibrate scanned maps
1) First, obtain a scanned map somewhere. GPSy 3.0 with QuickTime 3.0 supports the following file formats natively:
• PICT
• TIFF
• JPEG
• GIF
• Sun, SGI, Photoshop
GPSy 3.0 currently uses a one degree polynomial for its geomapping correlations. That means that GPSy 3.0 works best with maps that have relatively straight latitude and longitude lines. Universal Transverse Mercator and Transverse Mercator maps such as those produced by the USGS tend to work well. A future release of GPSy will use higher degree polynomials.
2) Locate three known points on the map. Write down their latitudes and longitudes. The three points should not lie in a line and should look as much like an isoceles triangle as possible.
3) Open the scanned map in GPSy using the "Open Map" command.
4) GPSy should open the file required. If the file is large and GPSy's memory allocation is small, then this may can up to a minute or two to open.
5) The map is zoomable and scrollable. To zoom in, hold down the Apple key and use the '[' and ']' keys to zoom in and out. The scroll bars should work as in other Macintosh applications
6) To calibrate the map, hold down the option key while clicking on the three known points (in step #2). Enter in the coordinates in the panel that comes up.
7) After the three points have been entered, the map should now work as a calibrated map. You current GPS location should be indicated by a lousy red + sign. Future releases will have a more nifty icon.
8) Be sure to save your calibrations. Select "save" from the File menu. Save the file with a separate name as your image file. Your calibration file will contain a pointer back to the original image file, so if you open the calibration file, it'll automatically open the image file. This is handy when the image file is on a read-only media such as a CD-ROM or DVD.
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Notes on scanned images:
1) Give GPSy as much memory as possible. Select the GPSy application in the Finder and "Get Info" from the File Menu. Give GPSy at least 1 megabyte + the uncompressed size of the image file you want to open.
2) If GPSy has less memory than needed to open the full version of the image file, then it will derez the image in order to make it fit in the memory available. This means that if you don't have enough memory, you'll be presented with a lower resolution image than the original file. Increasing GPSy's memory allocation or decreasing your color depth in your Monitor control panel will increase the resolution of the file.
3) GPSy's native file support is extremely fast when scrolling, with the payoff of a larger memory footprint. However, you can change the footprint in #2 as noted, with the payoff of lower resolution. It is impossible to have all three at the same time: 1) fast scrolling; 2) low memory requirements; and 3) fast file opens. Please send comments if you disagree with the tradeoff made in GPSy.
In comparison, note that while GPSy only needs 1 megabyte + the uncompressed memory size of an image (derezable to conserve memory); applications such as PhotoShop require twice the full memory size of an image, at least (although Photoshop has a virtual memory scheme that's slow).
4) GPSy's one-degree map polynomial algorithm works best with small-scale maps such as a city or state, rather than an entire nation or continent. We'll be moving to a higher degree polynomial in future versions of GPSy.
5) BSB map support and GeoTIFF mapping support and auto-calibrating to come soon.
DeLorme® StreetAtlas® and Tripmate® support provided under license from DeLorme Mapping, Inc.
Please note that IN NO EVENT SHALL SOFTWARE AUTHOR BE LIABLE TO USER FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGE, INCLUDING, BUT NOT LIMITED TO, LOSS OF REVENUE AND LOSS OF PROFITS, OR LOSS OF LIFE OR PROPERTY, EVEN IF AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. In other words, don't use GPSy for mission , life-critical, or plain stupid purposes (e.g., flying blind at night with only a GPS unit and GPSy to guide you; delivering pizzas in a bad neighborhood; driving while looking at a laptop) unless you are willing to acknowledge that it may produce miscalculations or results with unforeseen or grave consequences.
This product is not provided as either a primary or professional navigation aid and should not be used as such. Liability arising from the use of this product is limited to the purchase price of this product.
