Article published in the magazine Planeta MTB
GPS FOR MTB
Today it is difficult to find a group of adventurers or hikers without any members that includes a GPS tracking system in your hands. The mountain bike is not less, and they are increasingly users that include a GPS as a fundamental element to perform and record their routes. But do you really know how to use and handle their functions? For what and how is a GPS? Takes note of our expert and enjoy even more of your routes with greater security.
We will start giving an overview to the advantages of using a gps, peculiarities and equipment recommended, but let's go point by point:
Advantages of using a GPS mountain bike
GPS (Global Position System) brings big benefits in the calculation of distances outdoors. Result of the need to take positions with precision, the US Department of Defense developed the GPS system that currently covers around the world with about 3 metres horizontal precision.
In the beginning these data only showed numerically, i.e. expressados in latitude/longitude * (* l/l) that exported on a map calibration l/l determined the position with a civilian precision of 100 meters, but other times that were…
With existing equipment, we can directly see our position on a map within our GPS and I repeat, with a precision of error of (+-) 3 meters.
This precision is kept traveling great distances and does not need calibration or varies with the tire pressure, but with successive positions gives us the distance traveled and calculates the speed of actual displacement in horizontal position.
The less accurate data that handles GPS is height, hence which incorporated the altimeter, being recommended appliances if we want to accurately height information, although more least significant mileage will be accumulated height calculation error on some models.
Once the tour above the ground can be calculated an index of difficulty from 0 to infinity or even compare two routes from www.ibpindex.com.
There are programs that allow us to calculate the height via elevation maps.
It is recommended not to initiate any action until our GPS have good signal reception in long enough to determine its position.
GPS need to know where each and every one of the 24 satellites that make up the constalacion NAVSTAR, data received via Radio frequency outdoors with direct view of the sky or by placing it against a window, although it takes more time.
The system has been designed for outdoor use and can have limited coverage areas such as narrow streets with tall buildings, gullies or thick forests where GPS does not correctly receive the satellite signal, like underwater, although thanks to important technological advances, it is difficult to run out of coverage one we have position.
Starting to navigate:
When the Gps position, processes it and automatically record every second, storing movements according to the applied settings, which can be by time or distance, thus creating a visible path on a map of own GPS.
This trail GPS automatically stores is known as Track, being a set of points where to store coordinates (Lat/lon), time and height.
The height is less precise data, with a variation of up to 40 meters, hence the recommended use of the altimeter in all the GPS where the height is a relevant piece of information, though from an appropriate management programme it can be cured.
Also GPS if it is only not able to perceive changes in direction without displacement, i.e. the orientation or direction without a built-in Compass (electronic compass). Moving GPS gives very precise directions from 4 km/h.
So the Track is the way in which the device stores the route, although we can also make our position as a point of interest, the Gps will register with an icon and name (or number) default by calling Waypoint, this element can create and edit on-site, share online or create it on the map or specific program.
If we take one step further and combine several waypoint we can create another element of navigation in Gps and create a route, equally in the device or Pc program, since each manufacturer offers this solution as we shall see.
The right software allows you to create a track previously, even edit your points including icon and name, obtaining in this way to add valuable information available both visible on a map of our Gps and navigation displays data fields. Otherwise we will have to stop, find the area on the map, mark a waypoint and measure the distance.
Orientation and the calculation of time improves considerably if we have the midpoints, as beginning and end of descent, crossing points, changes of direction, relevant or even the diversion of the main track.
It is also very useful both in leisure or competition to avoid errors in downhill at high speed, where it is easy to deviate from the road and having to retrieve several kilometers of altitude at a critical time.
The gpx format allows you to associate multiple items in a file, as it would be a set of wpt and a track, also you can navigate a route to have the partial or crossing points and take the track visible on screen.
Until recently available for navigation items were listed, the Waypoint or route where we sail in a straight line and Track where we sail in relation to the nearest point. Now we can develop a digital Roadbook with CompeGPS Land for teams with TwoNav software, or in the case of Garmin and Alpine Topo Maps can look toponyms (points of interest) and get directions guided automatic. Also, thanks to the community of users Gps can download free countless Tracks from www.wikiloc.com
Forms of use of the GPS:
We can choose models with a range of up to 20 h. submitted to the configuration and above all to use, it is not the same follow a twisty track where we are forced to continuously vary the zoom, sailing from the map in track-up mode screen that follow a path marked tracks with figuring the north up or even to follow him from the processor of the navigation data (data page) route.
Lighting conditions of our navigation to determine brightness and suitable contrast and savings or consumption of batteries, like the times that touch the screen in the case that is tactile, conversely provided will be the duration of the batteries.
Recommend carrying spare battery or batteries on planned routes of more than 3 hours of browsing unknown, correctly configure the backlighting and to the extent possible alternate navigation stretches little demanding using the page of data with the aim of prolonging the autononima.
In the latter case highlights the usefulness of the route to cover long distances, and if we create it correctly resolvara the doubts of guidance and help make better decisions the ground, Gps and the maps are an aid to navigation and in no circumstances determine the reality, they bring us closer to it.
Coordinates and GPS:
Finally we will talk about coordinates, it is the system used by the Gps to calculate or check our position for example to mark a Waypoint. You can edit this information, with the consequent change of location of the item on the map.
The coordinates are displayed in the format defined in the configuration of the system.
If they are geographic or fleeces will be in degrees, by dividing the Earth in 90 ° North or South and 180 degrees East or West, and can be expressed in degrees, minutes and hundredths 40 ° 25,762' degrees minutes and seconds 40 ° 25' 43 "or 40.42969 grades
In this case we work with angles in reference to the Ecuador and the meridian of Grenwich, and used different formats depending on the scope and precision required, thus dividing a minute in seconds we have 60 parties, but dividing it into thousandths will be 999 parts.
If it is in linear or Cartesian coordinates as the UTM first it will make reference to a grid used to divide the land into sections with a number and a letter and then in reference to the East and North of the grid where works with the system metric, easier in the calculation of distances on the ground 30T 439713 4471999.
Mention that the format that we choose coordinates is relevant when it comes to cross external data, such as the paper map or to give our coordinates to a third party, mention that the Gps system does not need to distort reality by projections, contrary to the Cartographic maps using spheroids depending on the country to adjust the shape of the map and keep their distance.
If necessary we will have to take into account spheroid or map, Gps uses the WGS 84 Datum, usually paper or guide map hiker in our country uses the Datum European 1950.
We can find GPS in various formats, if our goal is to train both watch as the computer or GPS training meets its objective, in both cases they tend to include heart rate and Cadence sensors and admits data via Ant + power sensor.
If our goal is to improve the adventure and orientation the best is a dedicated GPS. Apart from the screen size and tightness, we can find them with touchscreen or specific function keys, let's see some of them:
Garmin Dakota 20
Excellent quality/price, touchscreen 2.6 '' great visibility in bright sunlight, it is robust and with 2 batteries AA gives a range of up to 20 hours. Not included, detailed neighborhood maps Topo Spain preferred scale 1:25 k or TopoAlpina. Optional Cadence and heart rate sensors.
TwoNav Sportiva and Sportiva +
3 "touch screen stands out for its lightness and luminosity, rechargeable batteries and 1/5 maps Spain IGN 1: 25 k, in addition the CompeGPS Rmap format makes virtually unlimited the possibility of adding user maps and available in different catalog publishers as Alpina, Sua, or Tienda Verde. If we want to further our training data we have to opt for the Sportiva + sensors including HR and Cad and which accepts the power sensor data via ant +.
With 3 '' screen and 16 hours of autonomy, the range of Garmin admits cartography Topo Spain, which includes detail to scale 1:25 k and is adapted fully to the screen to its optimum performance and display. Access information available onscreen elements so visual and tactile, such as toponyms or terrain features, for example curves of level and types of roads.
These models also includes European cartography at scale 1:100 k, very useful if our movements are asked to provide additional information on the main points, the 550 includes 3.2 megapixel camera.
Touchscreen display 3.5 "and keys direct function, very useful in adverse conditions and great adventures, 20 hours autonomy, includes topographic 1: 25,000 maps and rutables of Spain, in addition to the CompeGPS Rmap format for maps also available maps and user publishing different hikers com Alpina, Sua, or Tienda Verde.
SatMap Active 10
Screen of 3.5 "and access keys direct, ideal for those who do not want to touch screen. Includes map IGN 1/5 Spain 1:25 k, powered by 3 AA batteries or optional lithium Gel pack. Available maps Alpine publishing.
Novelty and top by their incredible 4 '' screen. There is no great adventure in which this device is over, your screen automatically orients itself thanks to the built-in rotation sensor. It accepts Topo Spain and Alpine Topo Maps.