A few days ago we saw How to capture data With Mobile Mapper 6, now we are going to try post-processing. For this it is required to have the Mobile Mapper Office installed, in this case I am using version 2.0 that comes with the purchase of the equipment.
The most practical way to do this is to use the Prolink, although if the data is being stored in the external memory, it is more functional to take the SD card and take the files from there.
Upload data to the Mobile Mapper Office.
Previously I explained the functionality of the different formats, all the data is stored in the .shp files but the .map files are the layer containers, so if the files are downloaded to the same folder, by opening the .map we will be able to have the layers that had been configured. (Just like a gvSIG .gvp does)
To load them in the Mobile Mapper Office, it is selected from the blue button.
If you do not want to download the project, you can create a new one with the option "New"And then load the layers.
As you can see in the graphic above, in the left panel you can turn off or turn on the .shp layers, while on the right you can change the fill or line color property.
Post-processing of data.
To load data for Postprocess, The button is used Add remote raw data, with which we can select the .grw data that saved the GPS. These are reflected in the lower part of the panel, both its initial and final hours.
To load reference data, the following button is used, which allows, on the one hand, to load available data, such as:
- Raw data in the Ashtech format (b *. *)
- RINEX raw data
The other option is to download data from the web, if we have an Internet connection. Here it is possible to set the number of stations or also the kilometers around; then the system begins to look for stations that have data available for those hours in which we have captured information.
There it goes, searching in the data station RINEX ftp of the NOAA Cors stations, of course being in the United States or Spain would do wonders, as there are more stations nearby serving information on the Internet.
See how, by giving the option of 7 stations, the IGS server in San Salvador identifies me, I suppose it is the CNR server at 168 kilometers. There are also two servers in Guatemala and two in Nicaragua, with the difference that those are 242 and 368 kilometers away. All taking data every 30 seconds, it is clear that none of these distances are acceptable for serious work, data from a closer base is required.
Once you choose which one to download, then select it and press the button Download. There you can see how the time scale matches the data, once this is done you just have to press the button Start process, And wait for the treatment to end.
See this example, it is a parking lot measured four times, the blue lines correspond to survey using shots every 1 second. The triangles correspond to the real information, taken with a Promark equipment with millimeter precision, just in the same period of time.
When doing post-processing, see what happens, this correction adjusts the object stored in the GIS layer, that is the shape file, which modifies its geometric data, but not its tabular data stored in the dbf.
It is interesting that the relative distance without post-processing is less than one meter, if taken in equivalent times. But the absolute error is between 3 and 5 meters, when doing the post-processing it drops to less than one meter.
Not bad for a team that goes below US $ 1,500 (The Mobile Mapper 6) The second example is taken from an exercise Discharged from the Magellan page. Clarification, when buying a team of these, you must ask that the post-processing is activated, as it is paid separately.