Questions tagged [c++]

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1answer
38 views

Any algorithm to draw lines inside a shape? [closed]

Let's say you have a circle and have all the coordinates (x,y) that make up the circle.... How would you create lines (vertical and horizontal inside it? What about a rectangle? What if you have the ...
2
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0answers
29 views

QGIS - How to render QgsMapCanvas on QApplication's main window

I am working with C++, QT 5.11.3, Visual Studio 2015 and QGIS 3.7 I'm trying to develop QT c++ application that uses the qgis api. I want to display simple raster and vector map in my qt application. ...
1
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0answers
14 views

Using QGIS C++ API to open .sfx

Trying to load layers from .SXF: QgsProviderRegistry::instance(qgisPluginPath); pLayerFromProvider = new QgsVectorLayer( filePath.toUtf8(), SL_LayerList.at(index....
3
votes
1answer
64 views

Seeking code behind Fix Geometries tool in QGIS?

I used the very nice "Fix Geometries" tool in the Processing Toolbox of QGIS 3.6 to repair a vector layer that was giving me trouble. The tool in QGIS worked just fine, but I was hoping to find out ...
0
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0answers
22 views

Calculating pitch and roll in ArcGIS Runtime?

For a more realistic movement it is necessary to calculate the roll and pitch. How can I do this by knowing the coordinates of two points? my code: void ViewshedGeoElement::animate() { // if (...
0
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0answers
23 views

Is it possible to edit a dimension's data type from pdal?

I'm working in a viewer based in potree with entwine, and i want to have HeightAboveGround (HAG) as a additional information, without replace Z in the LAS data. The target is to show the elevation and ...
1
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0answers
155 views

How to calculate OSM WGS84 Lat and Lon to meters in C++?

Summary I am converting OSM coordinates into X and Y values with accurate distances in meters between all points using c++. The calculations/code I am using is resulting in an incorrect ratio/scale ...
1
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1answer
17 views

How to catch the event the mousePressEvent on Esri :: ArcGISRuntime :: Graphic?

All events mouse protected. I tried to do it via eventFilter and using QObject :: connect, but the result false. How do I catch a click event on Graphic? What I tried: ... void ViewshedGeoElement:...
0
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1answer
50 views

Getting PNG binary data from GDALDataset

I have an in memory GDALDataset of driver type PNG. How can I get the binary PNG data to send to a web client without first writing the GDALDataset PNG to disk and reading it back as a binary file?
4
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1answer
82 views

How to generate triangulation file via QGIS C++ API

I created a plugin few years ago in Python. The plugin uses QGIS interpolation and works for QGIS 2.18. But because the QGIS interpolation creates raster (grid) and I need only Triangulation (TIN as ...
1
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1answer
42 views

How to install the QGIS C++ API for Visual Studio

I've recently being trying to get the C++ API working in Visual Studio, but there really not allot of information out there. I've found these code examples https://github.com/ranchodeluxe/...
2
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2answers
86 views

Got Pacman instead of circle when buffering point QGIS 2.14 standalone C++ application

QgsVectorLayer *circleLayer = new QgsVectorLayer("Polygon", "Circle", "memory"); QgsFeature circleFeature = QgsFeature(); circleFeature.setGeometry(QgsGeometry::fromPoint(geometryPoint)->buffer(...
0
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1answer
64 views

Get proj4 parameters from EPSG in C++

I have the EPSG number of the projection and I want to use proj4 to get the projection descriptive string (like +proj=lcc +lat_1=49 +lat_2=44 +lat_0=46.5 +lon_0=3 +x_0=700000 +y_0=6600000 +ellps=GRS80 ...
2
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0answers
15 views

Support materials and shaders in ArcGIS when importing model from 3D Max?

Does ArcGIS support materials and shaders when importing a model from 3D Max? Can I change the texture of the model when it is already added to the scene? How to do it? Esri::ArcGISRuntime::...
1
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0answers
20 views

QGIS 2.14 c++ standalone application crashes using QgsMapToolIdentify

lResultList.append(mpIdentifyTool->identify(lCoord.x(),lCoord.y(),QgsMapToolIdentify::TopDownStopAtFirst, QgsMapToolIdentify::VectorLayer)); leads to crash of app. It happens when layers provided ...
1
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0answers
19 views

zoomScale() doesn't work in QGIS 2.14 standalone c++ application

Can't set scale for my canvas with mapCanvas.zoomScale(50000); Seems like canvas is zooming to 1:1 and for a few seconds I can't zoom in or zoom out with mouse wheel. Any suggestions?
0
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0answers
33 views

How to use QT signals and slots in QGIS C++ API

I'm developing a standalone QT 5.11.2 application using QGIS 3.6 C++ API. I have defined a slot that is meant to consume a currentLayerChanged(QgsMapLayer * layer) signal. The slot declaration in ...
1
vote
1answer
41 views

How to set layer transparency QGIS C++ API 2.14?

I want to set transparency for already loaded layer by taking it from canvas QgsVectorLayer *myLayer = mpMapcanvas.layer(0); myLayer.setLayerTransparency(50); myLayer.triggerRepaint(); but get an ...
0
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0answers
44 views

How read a raster [Tiff] file to get the correct values for every band? [duplicate]

I am trying to read a raster tiff [RGBA] file with GDAL in [C++], I can load the file, get the number of channels, the size of the bands and the metadata, but when I try to extract the Band [R, G or ...
2
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1answer
33 views

Problems with layer labeling QGIS standalone C++ application

mypLayer->setCustomProperty("labeling", "pal"); mypLayer->setCustomProperty("labeling/enabled", "True"); mypLayer->setCustomProperty("labeling/fontFamily", "Cantarell"); mypLayer-&...
2
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0answers
71 views

Fill masked array values with reflect padding

I have a square matrix (image) with masked values in an area. The mask corresponds to missing values in areas close to the border (always). I want to create a new image where the masked values are ...
0
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1answer
75 views

Difficulties working with QGIS 3.4 API

I want to work with QGIS 3.4 in a C++ Qt project, but the API in version 3 has been completely changed and the sample code for older version don't compile anymore. Is there some sample code which ...
0
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0answers
13 views

Optimize A* on a large scale data

I am working on Develop a path finding system on data with about 80,000,000 links. Now I use bidirectional A* to find the path, but it's still to slow. Anyone have a idea?
1
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1answer
55 views

mapCanvas().DestinationCrs().authid() returns nothing

I want to do some work with projections in my c++ application with QGIS API v2.14. But canvas and layers didn't return their CRS. Even when I'm setting it to them with setDestinationCrs() for canvas ...
0
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0answers
39 views

Adding 2d and 3d base map which includes map actions in Qt application using C++?

I would like to add a base map(Map in the background) to view geospatial vector data in a Qt application i.e written in C++. I have gone through the Qt documentation here. I was only able to find 2d ...
0
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1answer
150 views

Constructing polygons from GDAL Polygonize?

I have a geotiff file, which, for each cell ( pixel), it contains a discrete value ( you can think of this value as the "fitness" value of the cell). For the neighboring cells, they can consist of the ...
1
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1answer
28 views

Show differenet SVG icons on one layer at runtime

I need to show several SVG icons (more than 388 icons) with different name on a single layer(if possible on memory layer). I am using QGis 2.8 and qt4.8.6 The icons represent different kind of ...
1
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1answer
70 views

Enabling C++ standards when compiling GEOS using cmake/ccmake?

I read from RFC # 7 of GEOS that the old autoconf based build system may be removed in the future, in favor of using cmake. I sometimes need to customize geos and add functions that uses the newest C+...
0
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1answer
171 views

Existing C++ libraries that convert ESRI shapefile to DXF/DWG [closed]

Is there any C++ library that can convert ESRI Shapefile to DXF/DWG file? I seek a link/or sample on how this can be done with the said C++ library. I'm aware that one can do this with ArcGIS ...
2
votes
1answer
72 views

Why do I have different maximum values for my TIFF file when importing with gdal?

I am importing a TIFF file into my programm and I am expecting a maximum value for the pixel values of 5.686229 because that's what I have when I read the file with QGIS. But then I get a maximum of 6....
0
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0answers
35 views

Open Local Raster Tile Layers with QGIS libs

I have tried my best to read all of the older posts before asking this question. I am a bit confused and I need a direction. from the older posts I have learned how to use SAS Planet to download the ...
4
votes
1answer
116 views

Improving QGIS source code efficiency?

I have noticed in the QGIS source code that the map layers gets added in two different places, in the Canvas and in the registry as follow: QgsMapLayerRegistry::instance()->addMapLayers(...
1
vote
1answer
110 views

C++ OGR GDAL Set spatial reference of new layer

When creating a new layer using OGR / GDAL in C++, how do i set the spatial reference? OGRLayer *poLayer2; poLayer2 = poDS2->CreateLayer( "layerName", NULL, wkbPoint, NULL ); if( poLayer2 == NULL ...
4
votes
1answer
101 views

Get a list of all supported EPSG code from OGR

I need get a a list of all supported EPSG code from OGR/GDAL. I need this becaouse i'm developing a C++ application map, and I need this information to put it in a user form. I read the OGR ...
1
vote
1answer
278 views

Using QGIS C++ API?

I'm trying to create a simple application using QGIS SDK. But currently, I'm stuck with API at very beginning stage. belows are the env. Windows 7 MSVC 2015 QGIS SDK (downlaod by OSGeo4w) include: ...
1
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0answers
124 views

Adding SpatiaLite to Visual Studio project (already has SQLite)

I am very new to SpatiaLite. I am working on a large Visual Studio C++ project that already supports SQLite, and I am trying to add SpatiaLite capabilities to it. After reading the documentation and ...
2
votes
0answers
115 views

How to use QGIS plugins functionality in standalone application

I'm new to QGIS 3 Library to develop standalone map application in qt4, C++ language. I was wondering if there is any way that I can use QGIS plugins such as Advanced viewshed analysis, Contour plugin ...
-1
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1answer
228 views

(c++) Advanced Geospatial Analysis Library [closed]

I've been searching for a lightweight library for geospatial analysis, with low overhead. Yesterday I found TurfJS, looks great, simple and fast, yet, its made in JS. Does anyone know similar ...
1
vote
1answer
145 views

Correct Qt version to build QGIS master

I just wonder wich version of QtCreator to install, current is Qt 5.11.1. Here I've read about building QGIS master with Qt 5.9.3 debug build: https://www.itopen.it/building-qgis-master-with-qt-5-9-3-...
1
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0answers
50 views

How to create GeoTiff from image and inertial data with GDAL

I am trying to position photos that have seconds of week (utc) in their name with a given inertial data from a file, the file has the following columns: UTCTime Easting Northing H-MSL Roll ...
1
vote
1answer
359 views

How to open .hgts file from NASADEM data

I have the NASA SRTM1 data as .hgt files from their ftp website, but I would have these elevation data in respect to WGS84. I found by NASA's ftp site a folder named srtmOnly that contains what I want,...
0
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1answer
52 views

Identify spectral bands in a multispectral raster dataset

I'm trying to make an application to use on precision agriculture using gdal, and want to give it some flexibility to support imagery from different providers. I've been looking around if there's a ...
0
votes
1answer
47 views

Can I change the level of detail of shapefile with OGR?

I`m working in a project where I must display shapefiles. I'm using OGR to read the shapefile data and use QT to display it. At this moment, I can display correctly shapefiles with around 2000 ...
1
vote
1answer
130 views

GDALOpenEx define papszOpenOptions

I'm using GDAL/OGR to open shapefiles. Now i'm calling this method to open a dataset: dataset = (GDALDataset *)GDALOpenEx(path.toStdString().c_str(), GDAL_OF_VECTOR, NULL,NULL, NULL); I read in http:...
1
vote
1answer
92 views

Calling GDALOpen from a function

I'm trying to call GDALOpen from a function to open a tiff raster and then use the dataset further in my main or other functions. This is the code I have so far: int main( int argc, char* argv[] ){ ...
1
vote
1answer
386 views

Most efficient way to split a polygon with lines, C++ API

I'm looking for the most efficient way to split a polygon (possibly with holes) with a set of lines (which can intersect) in C++ with GDAL/OGR or any other library which can prove useful. As shown in ...
-2
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1answer
171 views

Visual C++ runtime error

I had a working ArcGIS installation on my computer. Suddenly one day this error occurred. Runtime error! in Microsoft Visual C++ Runtime Library . I have reinstalled ArcGIS, reinstalled all the ...
0
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1answer
409 views

Set Metadata domain with GDAL (python bindings)

I'm trying to set geolocation metadata in a gdal vrt with python bindings. ds = gdal.Open('foo') ds.SetMetadata ({'X_BAND' : '1'}) gdal.BuildVRT('bar', ds) Results in a vrt with the following ...
1
vote
1answer
86 views

Unresolved externals on simple mapnik c++ application

I'm attempting to write a simple win32 x64 console application in c++ using VS 2017 that uses the Mapnik v3.0.9 SDK to render a png from a pgsql database. All I've done so far is include a reference ...
1
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0answers
108 views

Reproject map without resampling

I am going to build my on On-The-Fly projection system, just like QGIS's. A re there any C++ Libraries that will allow this? QGIS does not to resample the raster while on-the-fly reprojection, but to ...