[Qgis-user] red-lining / annotations plugin ?
Hi List, we often need 'simple' maps, where we get data from wms-servers, or provided by customers. Often we just have to make an image of the map, adding some simple annotations: - a (filled?) polygon or point - some text or labels added I'm missing that sort of functionality (plugin?). It would be nice if I could draw some features on the map, and add some labels or text. QUESTIONS: - has somebody been busy with this kind of stuff? - if not: should this be doable using the python plugin interface? - if so: I could't find python code examples in which there was actually some interaction between the mapcanvas and the plugin (aka: you draw a polygon on the map, and show some of it's properties in a plugin window or so). Can somebody give me a hand with that? TIA Richard Duivenvoorde ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
Re: [Qgis-user] Distorted Map Display
On Sunday 02 December 2007 4:02 am, peter wrote: I don't think I did the georeferencing correctly so I'll try it again. OK...I tried it again. Everything looks good but I still can't get the vector layer to display over the photo. It's like they're in two different extents. If I zoom to extent on the vector layer of the roads, I can see only the vector layer, and if I mouse over it, I see UTM coordinates. The scale says 1:138757 If I zoom to extent on the raster layer, I see only the photo, and if I mouse over it I see what look like x,y coordinates (some negative) that seem to represent the pixels of the raster layer. The scale says 1:79256 If I zoom in on the vector layer to the extent of where the photo should be, the scale reads: 1:24416 Here's what I did: - launched qgis, clicked the projector and set the project projection to NAD83 (CSRS)/UTM Zone 12N and checked the on-the-fly projection box. - started the Georeferencer plugin, selected Helmert to rotate the map, opened the .jpg, set eight points on the map with x = [the UTM easting coordinates], y = [the UTM northing coordinates] (which I got from the vector shape file that I opened later). - once it was done, I loaded the raster image. It popped up a dialog box saying, This layer appears to have no projection specification. I selected NAD83(CSRS)/UTM Zone 12N. It loaded the photo. - then I loaded the vector layer. The photo disappears and I only see the roads. The really strange part is that the first time I tried georeferencing this photo, but didn't select Helmert I was somehow able to get the roads to overlay the photo. Since then I have been unable to duplicate this even with the old georeferenced image. I have no idea what I am doing wrong. Any ideas? Thanks. Have you tried setting NAD27 instead of NAD83? It didn't seem to make any difference... -- Peter Pankonin, digitalcrucible There are 10 kinds of people in the world, those who understand binary, and those who don't. ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
[Qgis-user] GRASS Edit very slow when on the projection enabled
Hi Unless OTFP to a metric CS is enabled, area and distance measurements are forced in degress. Also the map scale displayed in the bottom-right corner of QGIS window changes while panning then (which I guess is normal as it impossible to have a constant scale in degree-based CS). The above are good reasons to have OTFP enabled most of the time, even if you actually don't want to reproject your vectors on the fly (ie. you have to set project CS to match your data CS and set OTFP on). However, a major negative side-effect is that GRASS Edit gets extremely slow with OTFP enabled, even when the CS of your vector data and the project are identical. Is it currently possible in QGIS to have working area, distance and scale measurements in metric units, along with GRASS Edit working fast enough? If not, I'd say it's a defect. Should I report it to tracker? QGIS SVN head 7709. Maciek ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
[Qgis-user] Dealing with multiple projections
Hey all, I'm having trouble wrapping my head around the workflow involved in dealing with multimple projections... I'm trying to create a map that I can load into my Garmin GPS, which (I think) needs to be WGS84. My data sources are mostly NAD83(CSRS)/UTM, plus I have some aerial photos that are NAD83/3TM. My first step was to reproject the Aerial photos to NAD83(CSRS)/UTM so that I can create new vector layers of the land features (mostly trails) and save those as NAD83(CSRS)/UTM shape files. Still having some trouble with this step... My next step would be to add those NAD83(CSRS)/UTM shape files to the rest of the NAD83(CSRS)/UTM shape files and then reproject and save those as WGS84 shape files. Does that sound correct or is there a better way to do it? Thanks much. -- Peter Pankonin, digitalcrucible There are 10 kinds of people in the world, those who understand binary, and those who don't. ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
Re: [Qgis-user] red-lining / annotations plugin ?
Hi Richard, On Dec 3, 2007 12:10 PM, Richard Duivenvoorde [EMAIL PROTECTED] wrote: QUESTIONS: - has somebody been busy with this kind of stuff? I don't know about anyone doing such support. But in fact you could use already existing QGIS facilities although the usage is not that straightforward as it could be with an annotation plugin: you can create new layers in QGIS and capture some points, polylines or polygons. You can also enable labeling so that some captured features can be drawn with text. - if not: should this be doable using the python plugin interface? Yes, surely. Map canvas API is really well-suited for this. - if so: I could't find python code examples in which there was actually some interaction between the mapcanvas and the plugin (aka: you draw a polygon on the map, and show some of it's properties in a plugin window or so). Can somebody give me a hand with that? Creating new map canvas items is not documented thoroughly but isn't hard. For start you can take a look at my simple QGIS-based program Quantum Navigator: http://mapserver.sk/~wonder/qnavigator/ There's also a screenshot of it - both flags on the start and end of the route are custom canvas items and they're done with just few lines of code. If you need one I'll try to create a small tutorial for creating custom canvas items and putting them to map canvas (and removing them). Regards Martin ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
Re: [Qgis-user] red-lining / annotations plugin ?
Hi Martin, Thanks for your answer, I'll have a look in your code this week. But it would be really helpful if you could provide a simple tutorial code project in which you interactively draw something on a mapcanvas (polylines/text?). So if you have some spare time the coming days ;-) This raises another question: what would be the best way to save this kind of stuff IIF possible). We could indeed save it in a postgres table (mixed geometries), or maybe in a set of shapefiles. But it would be nicer if there was a way to 'serialize/pickle?' stuff for example as part of the project file? Or as a separate 'annotations' file? Any ideas about that? I'm thinking on some dialog in which you can choose the geometry style (including text/labels) and the draw something on the mapcanvas. If the geometry is a line we could also show area/length (because current ruler and area tools are very 'light' at this moment). Another (helpfull) option would be to be able to 'copy' the generated labels into the 'annotation'-layer, to be able to adjust individual labels. Ok, thanks in advance, regards, Richard Duivenvoorde Martin Dobias wrote: Hi Richard, On Dec 3, 2007 12:10 PM, Richard Duivenvoorde [EMAIL PROTECTED] wrote: QUESTIONS: - has somebody been busy with this kind of stuff? I don't know about anyone doing such support. But in fact you could use already existing QGIS facilities although the usage is not that straightforward as it could be with an annotation plugin: you can create new layers in QGIS and capture some points, polylines or polygons. You can also enable labeling so that some captured features can be drawn with text. - if not: should this be doable using the python plugin interface? Yes, surely. Map canvas API is really well-suited for this. - if so: I could't find python code examples in which there was actually some interaction between the mapcanvas and the plugin (aka: you draw a polygon on the map, and show some of it's properties in a plugin window or so). Can somebody give me a hand with that? Creating new map canvas items is not documented thoroughly but isn't hard. For start you can take a look at my simple QGIS-based program Quantum Navigator: http://mapserver.sk/~wonder/qnavigator/ There's also a screenshot of it - both flags on the start and end of the route are custom canvas items and they're done with just few lines of code. If you need one I'll try to create a small tutorial for creating custom canvas items and putting them to map canvas (and removing them). Regards Martin ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
Re: [Qgis-user] Dealing with multiple projections
On Monday 03 December 2007 9:39 pm, you wrote: First, WGS-84 is a DATUM, not a projection. Ahhh...right. I'm still fairly new to all this. My apologies. The NAD83 datum, however, uses the GRS80 ellipsoid, and the datum parameters are very close to those of the WGS84 datum, and the ellipsoid is the same. H...that's what I've understood, except for when I select NAD83 on the Garmin, my waypoints are off by a few meters (specifically Geocache waypoints, that are provided in WGS83). Also, I've noticed that features like trails of other NAD83 maps I've loaded into the GPS, are not in the right place on the GPS screen (and it doesn't seem to make any difference if I select WGS84 or NAD83). With a little more specificity we might can help? The details are in my earlier post/thread called Distorted Map Display Why don't you see if you can reset the datum in your receiver to NAD83 and use a UTM representation? I'm using WGS84/UTM on my GPSr right now (as I mentioned above, waypoints are off by a few meters in NAD83/UTM or NAD83/lat-long). I suspect you're going about this in a rational manner but I think there are some missing details. Thanks... -- Peter Pankonin, digitalcrucible There are 10 kinds of people in the world, those who understand binary, and those who don't. ___ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
