QGIS » QGIS Application

I'd go with trying to apply it only for master ..
If there are small fixes for 1.7.x - ok - bugfix ..
but IMHO no UI Changes to a released version .. (probably others might think other)
regards
Werner

Hi Tim, and other interested parties,

Here is a patch file containing the fixes and improvements I have been working on. Most problems identified are fixed, but a few have not been as noted below. Perhaps round 2 will take care of them.

The patch was taken against my local copy of trunk, updated on 8/8/11.

As there are many changes to the UI, I agree that this should not be applied to version 1.7.x.

I am including a file that has some notes about these changes to the GPS tool for use in the User Guide.

The GPS tool works well visually as a floated window or docked by itself on the right side of the QGIS window (assuming no other widgets are docked there) if one wants to see all or most of the display fields.

Even though I don't have a gpsd data source available, I did check the operation of the edit boxes for the gpsd configuration and found a minor problem as noted below.

I would appreciate feedback on the modified GPS information tool, especially about whether the gpsd connection has any problems.

I have recently tested the modified GPS tool on a low-end AMD C-50 processor (dual-core, 1GHz clock) computer and am getting avg. CPU utilization <1%. It builds up to 5% or more if the track has a very large number of points (upwards of 5000 or so) to draw.
An Intel Atom processor (fake dual-core) based netbook runs around 3-4% indication.

There are a number of minor changes that I might not have noted. If you want more information on anything, please ask.

I have some observations on possible future improvements:

There is currently no interface to Python, so it isn't possible to do real-time GPS data processing with Python plugins, for example.

I believe that this tool should be split into three or more parts - a GPS connection module, a track log/feature addition module, and log file or other GPS data processing modules. The GPS connection module would establish the connection to a GPS device for other modules to hook into and display information like position and satellite graph.
It isn't practical to keep adding more ways to use the GPS data to this tool.
I believe this was the intent as there is a connection registry that allows other modules to use an established connection.

It is not a good idea to size or move the GPS Information window (or any QGIS window) while a GPS connection is active. This is due to the GPS connection handling being in the same event loop as the window (single-threaded application at present). This leads to loss of data while the event loop is suspended. May need to think about a separate thread for the GPS connection.

1. nmealib does not process fractional seconds of time properly - 0.70 becomes 0.07 for example
2. the cursor show/hide state isn't saved/restored
3. displayed track: if the map CRS is changed after some points are stored the track likely has incorrect coordinates. The user shouldn't have to think about this and probably doesn't even know that this could be a problem. Note that the list of points used to add a feature is not affected. - NOT FIXED - need to intercept the map CRS change and reproject the track points
4. there is a situation where a serial port (USB attached device with RS-232 emulation) has been detected by QGIS, but becomes disconnected before you attempt to Connect to it. There is no connection (there can't be, obviously) and it appears that the GPS detector doesn't signal failure. The connect button is in the connected state (toggled on), but its label is 'Connect'. It takes a click to return to the normal state. This is confusing behavior.
5. the gpsd Port edit box does not accept zero (0) in any position. Not a problem for the standard port, but for a non-standard port...
6. it is possible to hit the Connect button a second time before a connection attempt completes or times out, which will be confusing to the user. The button will be in the off state but may show Disconnect (if connection was successful) and would need two presses to disconnect. NOT FIXED. The obvious thing to is disable the button for the duration of the connect attempt until success or failure, then enable it. However, this seems like it could be confusing as well. And it will cause a transfer of focus to the next control in the tabstop order, which is also confusing.
7. I believe there should be a Help button somewhere (where ?) and associated help text. - nothing done yet
8. in Connect handling, the case of Connection, Serial device, but no device listed is not very good. A message box is popped about no path to GPS port, then unchecks the Connect button which now provokes the GPS disconnected status message. This could be a bit confusing. Since I discovered this very late (I thought I had checked this situation) I haven't tried to do anything. There probably should be a statusbar message about it and no message box. minor issue

1. removed the 'Live GPS tracking' action item on the View menu and reworked when and how the GPS Information dock widget is built. This allowed some objects and functions to be removed from QgisApp, so there is an API change (I don't believe that this really affects much). This also simplified the coding.
   Now the widget is always built on QGIS start and is shown/hidden from Panels on the View menu or the main window context menu, like various other tools, such as Browser.
   The original logic always built the GPS widget after the first use of it on a given installation.
2. nmealib fixed to parse fractional seconds correctly and to deal with thousandths of a second instead of hundredths
3. problem of disconnected serial port not showing failure is due to the immediate failure of the serial port open, which occurs before some signal/slot connections are set up. Removed the call to advance() in the QgsGPSDetector constructor, then in the Connect button handling call detector->advance() after the signals/slots are set up. Now there is a Failed to connect GPS status message virtually immediately on pressing Connect.
4. cursor show/hide state is now saved/restored
5. changed gpsd Port input mask from "ddddd" which only allows digits 1-9 to "00000" which allows zeroes. The mask "D0000" which I expected would require digits 1-9 in the first position actually inserts a space if a zero is typed in the first position. I didn't spend any more time trying to find a different mask.

1. removed the horizontal and vertical accuracy indicators - they had been hidden and are hard to interpret without a scale; on some platforms, were annoying due to animation; replaced with text value displays
2. moved Reset feature button to right of Add vertex, and set its tooltip to 'Reset track' - all this button does is clear the track object and list of points captured. It does not reset an added feature as it appears to imply.
3. relabeled the Add Vertex button to 'Add track point'; and the Auto-add vertices check box to 'Automatically add points' (this is in the Track group)
   reasons:
   a. vertex is a rather technical term and isn't used elsewhere, I believe, at least in the core QGIS.
   b. it operates on the track object, which wasn't exactly obvious
   c. to be consistent and distinguish track from features of a layer (the track may become a feature, of course)
4. further rearranged the Options page to place controls/grouping in what I believe to be a good order of usefulness
5. the 'Add feature' button tracks layer geometry type and editability for enabling it and changing its label - 'Add point' for example. This allows removal of a number of tests and their associated message boxes as the button can't be clicked if the layer type isn't correct or isn't in editing mode.
6. added data log file capability - this is very basic, with minimal error handling. The user must choose a file using a save as file dialog as there is no file name validity checking if the name were typed into a line edit box.
   The NMEA sentences received from the GPS are appended to the chosen file and have a ==== marker at the beginning of each chunk.
   The log file is opened and closed on GPS connect/disconnect.
7. added fractional seconds in date/time handling - this may be useful for some users if they have a GPS unit that provides fixes at >1 per second. fractions are not normally displayed, but see next item
8. added a date/time format string capability. This was used for testing the fractional seconds handling. the registry setting: /gps/dateTimeFormat
   this uses the QDateTime::toString() format coding. I have not provided any UI for setting this.
9. relabeled Elevation to Altitude on the Position page. I have looked at various GPS receiver manuals and find that Altitude appears to be more commonly used (and is actually the antenna altitude). Also, elevation can refer to satellite height in degrees above the horizon, which may be abiguous.
10. indicate units for speed and altitude in the display fields to avoid confusion
11. tooltips added to various controls, but not all. In particular, the page buttons and the position page fields have tooltips.
12. the Connection and Log file groups on the Options page are disabled while a GPS device is connected. This prevents changes to these controls, which could be confusing as they wouldn't affect the current connection.
13. added several members to the QgsGPSInformation struct for more detail; when cleared some members are given values that are to be considered invalid (the GPS unit would not normally send these values). These are used for determining whether a fix is valid.
14. in qextserialenumerator.h - changed the logic for MinGW compilation to eliminate compiler warnings about redefinition.
15. changed the settings location for track color and simplified color handling - from /qgis/gps/line_(color) to /gps/trackColour as a single value - so all GPS settings are together
16. changed track width setting so the value isn't saved on every change; now, almost all settings are saved in the destructor and restored in the constructor only; the exceptions: last port, log file path
17. I changed much of the Debug panel data handling while learning how this tool worked. Most of the changes are left in and most of the code is disabled by #if 0 blocks. I believe that the Debug part probably can be removed now as it is not shown to users and most of the information presented is shown elsewhere.
18. removed (by #if 0 blocks) some functions that weren't used or are no longer used

Steve

applied in ee215805d0a6a5871cbb072b28efa53c24f674e6 - with some tweaks, the QwtPolar update "broke" the patch.

Thanks again Steven.