- Again on the road Let's drive back on a normal road. The landscapes you can see in this area, especially at sunset, when the sun paints the sky in red, have delayed our planned tour.
The main phase of the test, for which we shall prepare a detailed report, will take place in Ariccia. It's here that the recording of "track log" will be really meaningful, because GPS receivers will be used in mixed tracks, consisting of urban and outdoor parts, in large road and small streets.
- Purpose The purpose of the three tests is to verify if the driving route corresponds to the track logged by PDA-GPS: the more the tracks overlap, the more the antenna is precise.
-Tools They are all free and easy to use. The tools we have adopted allow drawing a map containing a graphical representation of tracks. They can be used also by non professional users, in case you are interested in repeating directly our experience in other situations.
Let's see briefly the main features of the tools.
- VisualGPSce: it's a software, compatible with all the most recent operating system Windows Mobile, that saves in a text file all the information provided by a GPS receiver on a track: latitude, longitude, altitude etc. The "track log" can be further reproduced in a lab to identify all movements, as they have been received by the GPS (not necessarily they will correspond in full to the real track log). VisualGPSce has been installed on all the six devices used in this test.
- Google Maps: it is a service provided by the company that has developed the famous Internet search engine. It consists of a detailed cartography, that can be viewed on a web page. It can be used to determine addresses, points of interest and make routing operations.
- GPSVisualizer.net: this web site allows the uploading of track logs, that can then be reproduced in a graphical way with lines that represent the tracks. These can be overlapped to Google Maps, so that we can compare the tracks ad seen by the GPS receiver with the realist cartographic one.
- Instructions for the use of the map The map shown below represent the track driven during the test by the team of SoloPalmari. It starts before Ariccia, a small city close to Rome, and it ends in the centre of the town itself. The map is totally interactive, thanks to Google's technology. Here is a list of the main functions. We advice you to read carefully these instructions to test all the features, in some cases even unexpected.
- Zoom: the vertical bar on the left allows to increase or decrease the zoom details. With a lower detail you have a larger view on the whole track; the higher zoom level allows to view with more details the track recorded by VisualGPSce for every PDA. Attention: the higher zoom can only be used in "G. Map":mode; satellite images are not allowed to present data with great detail, due to privacy reasons.
- D-Pad: as with the buttons of a PDA, the group of buttons in top left position allows to move along the map in directions North-South-East-West. By pressing the star key you can go back to the initial position.
- Panning: to move inside the map or move to portions of the map currently not visible, you can use the mouse pointer: just click on the map, keep the mouse button pressed and move the pointer in the direction you want.
- Menu: it contains three elements, that allow you o select the image background. The options are "G. Map" (Google Map), which includes roads, streets, crossings, the name of some streets and of some location (like in a normal map); "G. Satellite" (Google Satellite) provides the view from a satellite image; "G. Hybrid" (Google Hybrid) is an intermediate format, that can associate both layers.
Legend: represents, in different colours, the track of each device. With a click on the title of the track you can select or deselect it. This function is useful in those cases in which, due to the high level of zoom, track overlap, and cannot be distinguished separately.
- Track log number 1: Mio A701, Mio A201, HP hw6515
In this first test we have compared three devices with integrated GPS: Mio A701 (red), Mio A201 (green), HP hw6515 (blue). The tracks are very regular, overlapping with the real one, for the first two devices. This is not true for the Pda-phone from HP: its track is always far away from the real route. The situation is even worse when, entering the village through an underway, receiving the satellite signal is really very difficult: in this situation the HP model gets lost. As justification for this, we must say that the HP hw6515 is the only one not to implement the efficient SiRF Star III, but rather an AGPS Global Locate receiver.
