Importing Images
Point Editor
Projections
Tucson Sample File
Downloading Images and Maps from MicroSoft TerraServer
Images can be imported into GPSXtended to be used as a background mapping image. The program imports and uses bitmap images in the MicroSoft BMP format. These images can be obtained from any source and imported into GPSXtended through the PC interface.
GPSXtended creates an image library to track and georeference images. The image files are then stored in the GPSXtended file format *.GPS. The loading of images into the *.GPS file is a two step process. First the file is loaded into the program and displayed. The file is then georeferenced.
Step 1. Load images using the Open GPS.
Step 2. Georeference the images. To georeference the image you need pieces of information. The size of each pixel on the ground (ground resolution) and the location of the pixel of the top left corner. This information is provided in the world files provided with georeferenced images. Enter the Pocket PC Storage Location to identify the location of the images on the Pocket PC.
Sample of world file georeference information.
1.00000 resolution use this number for ground resolution
0.000000
0.000000
-1.000000
505500.000000 x-coordinate value for the left pixel
3568200.000000 y-coordinate value for the top pixel
Tip: Use the Apply to All buttons to copy the resolution value and Pocket PC Storage Location to all images in the library.
Using ActiveSyn or your PC connection to the Pocket PC. Copy image files to the appropriate storage media. See your Pocket PC documentation and File Explorer for information of naming of Pocket PC media. The name of the location must match that given by Pocket PC Storage Location
Point Editor for the PC version of GPSXtended provides a method a to import and export GPS points from and to the Pocket PC. The editor allows the users to import and export points, input points manually and manage existing point on the GPS database that can be shared with the Pocket PC. GPSXtended supports DXF and ASCII text in a comma delineated format.
This tool allows you to change between geographic projections for the Point Files. The points can be changed between Geographic Projections, UTM and State Plane in NAD27 and NAD83 datums.
Included in the program file set is a sample of Tucson Files. The set includes the following files.
Tucson Sample.gps |
A gpsxtended GPS file with sample points and images |
A1.bmp-A5.bmp | Image files 1 meter ground resolution from Terraserver |
DXF Export of Tucson Sample.dxf | DXF export file from PC version of Point Editor |
ASCII Text export of Tucson Samples.txt | ASCII Text file comma delineated |
Shown below are exported points displayed on the A2.bmp image. See tutorial for more information on using GPSXtended.
Images for GPSXtended can be downloaded from Microsoft TerraServer. These files are distributed from the USGS and are free of charge. To download these files follow the instruction on the TerraServer Site. Remember to record the information from the World File when downloading the images. Save images in BMP format.
For many urban areas the site contains images with submeter resolution. These files work particulary well for field survey and data collection.