Complemento GPS¶

O que é GPS?¶

GPS, the Global Positioning System, is a satellite-based system that allows anyone with a GPS receiver to find their exact position anywhere in the world. GPS is used as an aid in navigation, for example in airplanes, in boats and by hikers. The GPS receiver uses the signals from the satellites to calculate its latitude, longitude and (sometimes) elevation. Most receivers also have the capability to store locations (known as waypoints), sequences of locations that make up a planned route and a tracklog or track of the receiver’s movement over time. Waypoints, routes and tracks are the three basic feature types in GPS data. QGIS displays waypoints in point layers, while routes and tracks are displayed in linestring layers.

Carregando dados GPS de um arquivo¶

There are dozens of different file formats for storing GPS data. The format that QGIS uses is called GPX (GPS eXchange format), which is a standard interchange format that can contain any number of waypoints, routes and tracks in the same file.

To load a GPX file, you first need to load the plugin. Plugins ‣ Plugin Manager... opens the Plugin Manager Dialog. Activate the GPS Tools checkbox. When this plugin is loaded, a button with a small handheld GPS device will show up in the toolbar and in Layer ‣ Create Layer ‣ :

• ^{GPS Tools}
• Create new GPX Layer

For working with GPS data, we provide an example GPX file available in the QGIS sample dataset: qgis_sample_data/gps/national_monuments.gpx. See section Amostra de Dados for more information about the sample data.

1. Select Vector ‣ GPS ‣ GPS Tools or click the ^{GPS Tools} icon in the toolbar and open the Load GPX file tab (see figure_GPS_1).

2. Navegue até a pasta qgis_sample_data/gps/, selecione o arquivo GPX national_monuments.gpx e clique ** [Abrir]. **

Figure GPS 1:

The GPS Tools dialog window

Use the [Browse...] button to select the GPX file, then use the checkboxes to select the feature types you want to load from that GPX file. Each feature type will be loaded in a separate layer when you click [OK]. The file national_monuments.gpx only includes waypoints.

GPSBabel¶

Since QGIS uses GPX files, you need a way to convert other GPS file formats to GPX. This can be done for many formats using the free program GPSBabel, which is available at http://www.gpsbabel.org. This program can also transfer GPS data between your computer and a GPS device. QGIS uses GPSBabel to do these things, so it is recommended that you install it. However, if you just want to load GPS data from GPX files you will not need it. Version 1.2.3 of GPSBabel is known to work with QGIS, but you should be able to use later versions without any problems.

Importando dados GPS¶

Para importar dados de GPS de um arquivo que não é GPX, você irá usar a ferramenta: guilabel: na caixa de diálogo Ferramentas GPS. Aqui, você seleciona o arquivo que deseja importar (e o tipo de arquivo), e onde você deseja armazenar o arquivo GPX convertido e qual o nome da nova camada. Note-se que nem todos os formatos de dados GPS irá suportar todos os três tipos de recurso, portanto, para muitos formatos você só será capaz de escolher entre um ou dois tipos.

Descarregando dados de um receptor GPS¶

QGIS can use GPSBabel to download data from a GPS device directly as new vector layers. For this we use the Download from GPS tab of the GPS Tools dialog (see Figure_GPS_2). Here, we select the type of GPS device, the port that it is connected to (or USB if your GPS supports this), the feature type that you want to download, the GPX file where the data should be stored, and the name of the new layer.

Figure GPS 2:

Ferramenta de download

O tipo de dispositivo que você selecionar no menu do aparelho GPS determina como GPSBabel tenta se comunicar com o seu dispositivo GPS. Se nenhum dos tipos disponíveis funcionar com o seu dispositivo GPS, você pode criar um novo tipo (ver seção ref: definindo-novo-dispositivo).

A porta pode ser um nome de arquivo ou algum outro nome que o seu sistema operacional utiliza como referência para a porta física em seu computador que o dispositivo GPS está conectado. Também pode ser simplesmente USB, para unidades de GPS habilitados para USB.

• On Linux, this is something like /dev/ttyS0 or /dev/ttyS1.

• No Windows, é “COM1” ou “COM2”.

When you click [OK], the data will be downloaded from the device and appear as a layer in QGIS.

Carregando dados no receptor GPS¶

You can also upload data directly from a vector layer in QGIS to a GPS device using the Upload to GPS tab of the GPS Tools dialog. To do this, you simply select the layer that you want to upload (which must be a GPX layer), your GPS device type, and the port (or USB) that it is connected to. Just as with the download tool, you can specify new device types if your device isn’t in the list.

This tool is very useful in combination with the vector-editing capabilities of QGIS. It allows you to load a map, create waypoints and routes, and then upload them and use them on your GPS device.

Definindo novos tipos de dispositivo¶

There are lots of different types of GPS devices. The QGIS developers can’t test all of them, so if you have one that does not work with any of the device types listed in the Download from GPS and Upload to GPS tools, you can define your own device type for it. You do this by using the GPS device editor, which you start by clicking the [Edit devices] button in the download or the upload tab.

To define a new device, you simply click the [New device] button, enter a name, enter download and upload commands for your device, and click the [Update device] button. The name will be listed in the device menus in the upload and download windows – it can be any string. The download command is the command that is used to download data from the device to a GPX file. This will probably be a GPSBabel command, but you can use any other command line program that can create a GPX file. QGIS will replace the keywords %type, %in, and %out when it runs the command.

“% type” será substituído por “-w” se você estiver baixando “Locais”, “-r” para “Rotas” e “-t” para “Trilhas”. Estas são as opções de comando que o GPSBabel possui para download.

%in will be replaced by the port name that you choose in the download window and %out will be replaced by the name you choose for the GPX file that the downloaded data should be stored in. So, if you create a device type with the download command gpsbabel %type -i garmin -o gpx %in %out (this is actually the download command for the predefined device type ‘Garmin serial’) and then use it to download waypoints from port /dev/ttyS0 to the file output.gpx, QGIS will replace the keywords and run the command gpsbabel -w -i garmin -o gpx /dev/ttyS0 output.gpx.

Os comandos indicados nas linhas de ‘Carregar’ são aqueles utilizados para carregar os dados no dispositivo. As mesmas palavras-chave são utilizadas, porém %in é substituído pelo nome do arquivo GPS que é utilizado e %out é substituído pelo nome da porta.

Você pode aprender mais sobre GPSBabel e as opções de linha de comando disponíveis em http://www.gpsbabel.org.

Depois de ter criado um novo tipo de dispositivo, ele aparecerá na lista de dispositivos para baixar e atualizar as ferramentas.

Download de pontos/trilhas para GPS¶

Conforme descrito nas seções anteriores, o QGIS usa GPSBabel para baixar pontos / caminhos diretamente no projeto. QGIS abre a caixa com um perfil pré-definido para baixar de dispositivos Garmin. Infelizmente há um bug #6318 que não permite criar outros perfis, por isso o download diretamente no QGIS usando as ferramentas de GPS está no momento limitado a unidades USB Garmin.

ATTRS{idVendor}=="091e", ATTRS{idProduct}=="0003", MODE="666"

rmmod garmin_gps

gpsbabel -t -i skytraq,baud=9600,initbaud=9600 -f COM9 -o gpx -F C:/GPX/aaa.gpx

skytraq: Too many read errors on serial port

gpsbabel -t -i mtk -f COM12 -o gpx -F C:/temp/test.gpx
mtk_logger: Can't create temporary file data.bin
Error running gpsbabel: Process exited unsucessfully with code 1

gpsbabel -t -i mtk -f /dev/ttyACM3 -o gpx -F /home/user/bluemax.gpx

gpsbabel -t -i mtk -f /dev/rfcomm0 -o gpx -F /home/user/bluemax_bt.gpx