How to Scan and Upload Maps to Your GPS System

GPS devices pinpoint location, direction, and destination with maps purchased for the system. You can save money if you scan maps and then upload them to your GPS system. Here's how to prepare and upload GPS-ready maps.

Difficulty: Moderate

Instructions

Things You'll Need:

• Scanner
• GPS system

1. Scan clear original maps. Ensure the map's proper orientation with north forming the topmost page, and crop out map parts you don't need. Use a low-resolution scan, preferably 72 dpi, and preview the scan for clarity.

2. Save the scanned map as a bitmap file. Select a bitmap file format that occupies the least memory, such as JPEG or GIF. The file type must be compatible with your GPS device.

3. Determine the map's center. On the scanned map, draw diagonal lines linking the northern and southern map points so that the intersection is the center, and then calculate the center's longitude and latitude as accurately as possible.

4. Transform your bitmap file into a text file and include this HTML code: <|LT:12.34567|LN:-23.45678|LS:12345>. LT refers to the center's latitude, LN the center's longitude, and LS is the DISTRIBUTION/(BAR * 0.000015855408), with DISTRIBUTION referring to the scale used in the bitmap file, such as .5 or 1 mile divisions; BAR refers to the total divisions in your map. Save the file using the filename extension ".htm."

5. Open a folder in your GPS device and upload the bitmap and text file to this folder. Open the file menu on your GPS device and view the map.

Tips & Warnings

• Test the accuracy of your new map by comparing distances between the original and scanned maps. Look for points of comparison such as distinct locations and compare distances and directions.
• Test the accuracy of your uploaded map before putting it to actual use.
• Check the latitude and longitude information in the text file. You might end up in the wrong place.