An object-oriented programming language

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2answers
639 views

How to show a QGis map in Qt/C++ custom widget with QgsMapCanvas?

I'm trying to add a QGis map in Qt/C++ widget using QgsMapCanvas, but I have some problems... I'm working with the following environment: - Ubuntu 12.04 - QGis 2.8.1 - Qt Creator 2.4.1 (based on Qt 4....
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1answer
87 views

Getting Feature names from WFS in C++

to start off with: Coding in C++ Using WFS Version 1.0.0 Using QT 5.4.1 Windows 8 Latest versions I'm trying to read in a WFS in code via Gdal compiled with Xerces - I'm able to read the GML ...
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0answers
168 views

How to remove a QgsMapCanvasLayer from QgsMapCanvas with PyQGIS || C++?

I try to find a way to remove a QgsMapCanvasLayer from the QgsMapCanvas. At the moment I only can delete the MapLayer from the QgsMapLayerRegistry with: QgsMapRegistry::instance()->...
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0answers
65 views

QGis Application Debugging - missing source problem at setScene method in QgsMapCanvas class [closed]

I develop a app in C++ with Qgis components with VS2010 Prof on Windows 7. Compiling a release succeeded and the app´s behaviour is as expected. Nevertheless I would like to take advantage of the ...
0
votes
1answer
193 views

QGIS C++ Hello World example crashing

I have written a very simple C++/Qt application using QGIS comprised of a single "main.cpp" file as below: #include <qgsapplication.h> int main(int argc, char ** argv) { QgsApplication app(...
2
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3answers
655 views

Using GDAL/C++ to calculate distance in meters

I'm using GDAL in C++, with WGS84. I want to calculate distance between two points in meters. The code snippet below tries to find the distance between 25N/75E and 25N/76E. The code, as is, returns 1....
0
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1answer
78 views

What packages are required to install C++ API on Linux Mint 17?

What packages are required to install C++ API on Linux Mint 17? I already have access to the Python API (installed via “python-qgis” package), but no C++.
3
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2answers
722 views

How to convert latitude, longitude to EPSG 3857?

I'm looking to study the math involved to see how a given latitude and longitude in decimal degrees can be converted to epsg 3857. Can anybody point to a good reference or a possible python/c/c++/java ...
1
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1answer
145 views

Set up GDAL for C++ in RHEL

I've got GDAL installed from the latest 1.11.2 source, but when I try to make by C++ executable I get undefined references to "GDALAllRegister" and basically all the GDAL functions I call. The same ...
2
votes
1answer
119 views

Implement r.cross / ArcGIS Combine with GDAL

I am using GDAL to process a lot of rasters. I then need to combine all the arrays to create a single output raster that represents all the unique combinations of values. I.E the same thing as r....
1
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2answers
625 views

QGIS Rule Based Rendering

I am looking for an example of how to use the QgsRuleBasedRendererV2 to filter features of a layer based on an attribute value (0 or 1). Has anyone done this in Python or C++?
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0answers
129 views

GDAL, Georeferencing

I have been trying to use GDAL library to add geoinformation to an image. From the documentation from GDAL web page I could find that I could use GDAlSetGeotransform(), for that I need a six ...
2
votes
1answer
63 views

Loading Raster using QGIS API in Windows

I am trying to develop a C++ application using QGIS. I have to load a tif file and show it. First I wrote an app similar to samples on the internet. It works on Linux, but it does not work on Windows....
2
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0answers
155 views

Microsoft Visual C ++ Crash when Install qgis.2.8.1

I have installed and reinstall QGIS ver.2.8.1. and always display a message as shown below. I hope someone can help me fix these problems. Thanks for your help.
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0answers
46 views

QgsSpatialIndex crash my deploy C++ QGIS custom application on windows

When I use the QgsSpatialIndex class, after leaving the method, my application crash. Looks like the object QgsSpatialIndex class works, it brings QgsFeatureId list, but from what I noticed something ...
1
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1answer
223 views

Run C++ standalone application in debug mode

I write simple C++ standalone application using QGIS. It works and render vector layers from PostgeSQL database. #define CORE_EXPORT __declspec(dllimport) #define GUI_EXPORT __declspec(dllimport) #...
5
votes
2answers
2k views

GDAL in C++: Reading a ShapeFile

I am trying to use the GDAL Lib to read a ShapeFile (.shp). I followed the instructions of http://www.gdal.org/ogr_apitut.html - But it doesn't work! #include <gdal_priv.h> #include <...
2
votes
4answers
697 views

How to crop Geotiff image in C++ (GDAL or other possibilities)?

I am developing a code to process a geotiff image. But firsly I need to crop a geotiff image preserving its metadata (projection...) in C++. My idea it's to provide the corners and the geotiff image ...
3
votes
1answer
424 views

DEM creation with C++ application

I am implementing a C++ application that must produce DEMs from LIDAR data. I am following the next workflow: Write .las files from lidar data. Use PCL algorithms to transform/filter the point cloud....
1
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1answer
273 views

How to get values to create world file format?

i have researched regarding making world file format and tried to create one using c++ in windows, can somebody confirm if where i am getting the values from are correct? the literature regarding ...
1
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1answer
155 views

Georeferencing las files using liblas

I am trying to write georeferencing information to a '.las' file using liblas and c++. Here is my code: ofstream ofs; ofs.open("test.las", ios::out | ios::binary); liblas::Header header; ...
2
votes
1answer
226 views

How to make rectangle selection on QgsMapCanvas?

I have this code for create and open raster map: if(QFile::exists(rasterFileName)) { QFileInfo myRasterFileInfo(rasterFileName); m_pRasterLayer = QSharedPointer<QgsRasterLayer>( ...
1
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1answer
166 views

Why does GDAL Polygonize flip features vertically? [closed]

I am trying to convert a 1 band jpg raster into polygons. It is converting the data and I get a polygon shape file. However, the output data is vertically flipped. Input data have no reference system....
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0answers
95 views

How do I step into the C++ functions from an external Python app I'm debugging?

I just wanted to see how to step into the C++ class QgsVectorLayer()'s methods from the python call to QgsVectorLayer(self.uri.uri(),'foo','postgres'). I'm trying to debug and it trying to step into ...
3
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0answers
114 views

GDALRasterizeGeometries doesn't burn correct Values

What I have is a vector shape file with a string field. What I've done is written a CSV file with the field ID, field_value and now I would like to rasterize the vector layer as a byte raster with the ...
0
votes
1answer
468 views

Distance between a Point and Linestring: PostGIS/GEOS vs. Boost

I am currently using the GEOS library through OGR and data from a PostGIS database to work with geospatial data. I now found myself in the need to use some of the algorithms Boost.Geometry and Boost....
4
votes
2answers
266 views

Is there a GIS-Tool that fit my needs? [closed]

I´m working on a GIS-Project in the Defense & Intelligence sector. The goal was to develop/create a GIS-Service that: stores and manage GIS-Data (Map data, Height data.. ) has a repository for ...
1
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0answers
22 views

Getting incorrect results for Geary's Coefficient algorithm (incorrect math?)

I'm not sure if anyone here can help me with this, but I'm currently working on a program that uses a spatial autocorrelation algorithm to analyze patterns in an image. It's supposed to return values ...
2
votes
0answers
48 views

In version 2.4 vector layers with labeling switch off caching

I am developing a map display stand alone application using the C++ API. With version 2.6 the caching mechanism is ignored for vector layers with labels. The reason is to avoid conflicting labels. ...
2
votes
1answer
981 views

How to develop c++ standalone QGIS C++ Application

I want to integrate QGIS in QT\C++ application. I try to write basic C++ apllication to render map and build it using MSVC 2010. class PostGisViewer: public QMainWindow { public: PostGisViewer(): ...
0
votes
1answer
289 views

Generate delaunay triangulation from 3D(x,y,z) points

I have 3D Points array.each 3D point have x,y,z data. I want to generate delaunay triangulation.I am new in delaunay triangulation. My array as below. -256.24 85.35 5.0 -262.24 84.35 15.0 -263.24 87....
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0answers
28 views

Point Symbolizer() in rundemo.cpp file Giving error

The code is given Below: roads2_rule_11.append(point_symbolizer("abc.png")); The error is given below: rundemo.cpp: In function âint main(int, char**)â: rundemo.cpp:142:57: error: no matching ...
1
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0answers
54 views

when make a cross-platform c++ GIS core, how to make the 2d-drawing platform independent? [closed]

i try to develop a c++ no-GUI GIS core(i want the core have no GUI related things, do not use any GUI library) and I can figure out how to do other things except the drawing part. when cope with 2D ...
2
votes
0answers
66 views

What is the issue with geopdf format?

I'd like to add the geopdf format as output of a library that I am working on. After have looking around, I have not been able to find a (c, c++, python) library that meet my license requirements (...
0
votes
0answers
91 views

Syntax Error in qgsapplication file

I am trying to test an QGIS application code example. However, when I try to compile it, it is reporting errors in qgsapplication.h which is coming with the source code of QGIS. I am using QTCreator ...
2
votes
1answer
425 views

How to load a *.qgs file in a C++ QGIS standalone app?

I'm using QGIS-2.4.0 API to develop a standalone app by C++. I saved a test.qgs file in QGIS Desktop software, in the project, there was one layer and it was visible. Then I loaded the test.qgs ...
1
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1answer
51 views

What is a purpose of parameter 'separater' in mapnik csv plugin datasource?

What is the purpose of the parameter 'separater' in the Mapnik CSV plugin DataSource Example of the code: parameters p; p["type"]="csv"; p["inline"]=quotedStr; p["...
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0answers
62 views

What is a Format of csv plugin datasource string in mapnik

I have tried that Format Is that is a correct format to pass to CSV plugin,the sample C++ code is given Below: std::string csv_string("wkt,Name POLYGON((5.123456 51.6, 6.8 52.6, 7.8 51.6, 5.123456 51....
0
votes
0answers
309 views

Open a *.qgs project file in API, why maps do not show?

I'm using QGIS-2.4.0 API. I saved a test.qgs file in QGIS Desktop, in this project, there is one layer that is visible in it. Then I open the test.qgs project file in QGIS API to developing an App, ...
2
votes
1answer
246 views

How to write a custom canvas item for SVG marker by subclassing QgsMapCanvasItem in QGIS?

I want to subclass QgsMapCanvasItem for SVG marker in QGIS, I looked up a similar topic in stackexchange and QGIS mailing list, I found that this is similar to mine, I did exactly what @Nathan W did. ...
3
votes
1answer
1k views

Looking for QGIS 2.4 C++ Hello World example?

In the project I'm working on (C/C++/Qt application), we are trying to integrate QGIS (latest version desirable, 2.4 for the moment). But there is very little information in the web on how to use QGIS ...
2
votes
1answer
526 views

Add band to GDAL VRT dataset and convert to TIFF

I'm trying to add a band to a TIFF dataset by converting it to a VRT format and using the AddBand() function, then convert it back to a TIFF to access the band and write the data. Here is an example ...
2
votes
0answers
326 views

How to develop a real-time navigation App using QGIS API?

I want to develop a navigation application based on QGIS using C++, for live tracking. I think it is quite normal for GIS to do such things, especially QGIS as it is a very mature GIS platform. But ...
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0answers
193 views

How to create a svg item onto Map Canvas in QGIS API?

I'm working on a project with QGIS-2.4.0 API using C++. I need to load some svg files to the application for displaying as symbols. QGIS API has a class named QgsMapCanvasItem, which is an abstract ...
1
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2answers
350 views

GDAL Application crashes when loading GDAL drivers

I'm developing on QT an application that uses GDAL library (which I compiled using MinGW 4.8). When I use the application on my windows 8 laptop, it works fine, but when I tried using it on several ...
2
votes
2answers
810 views

Error getting ESRI Shapefile driver OGR in C++

I am unable to create an OGR Layer using the C++ API. I have followed the documentation at this link exactly http://www.gdal.org/ogr_apitut.html I get an error trying to get the shapefile driver. Any ...
0
votes
1answer
157 views

going from hillshade to percent shaded (gdaldem)

I assumed hillshades output percent shaded (scaled to 255) at the given azimuth and altitude but this is incorrect. A flat raster at 80 degrees altitude has a maximum value of 251 instead of 255. How ...
2
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0answers
150 views

How do you clip a gnomonic or stereographic azimuthal projection?

I have polygons comprised of lat/lon coordinates and I want to project them onto a plane that's appropriate for polygon operations (such as checking for intersections). In some cases, the polygons ...
1
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2answers
544 views

Does QGIS support dynamic display?

I'm a new developer of QGIS using C++. I am working on a project which needs to display dynamic maps/layers(just like GPS, but it is not GPS, however it should display data alike GPS data - dynamic ...
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0answers
159 views

Rendering a geotiff block with gdal and gdk-pixbuf - Some flaws in the result

I currently try to render a geotiff file with GTKmm\GDKmm (gdk-pixbuf). The file is a tiled geotiff with a block size of 256*256 and three rasterbands. The shortened gdalinfo output is: Driver: GTiff/...