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1answer
29 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; ...
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0answers
43 views

How I use point symbolizer for styling in mapnik c++ source code?

I have tried point symbolizer for styling in c++ mapnik source code ,the given code line : roads2_rule_11.append(point_symbolizer("/home/razaliaqat/raza.jpg")); But it is giving an error given ...
1
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0answers
32 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 ...
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0answers
19 views

Pass Data as a String Using Mapnik CVS Plugin

I am new in mapnik and c++ I need Help. I have a code written in C++ that read a data using postGis .The Sample Code is given Below: parameters p; p["type"]="postgis"; ...
0
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0answers
145 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
155 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. ...
2
votes
1answer
632 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
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1answer
258 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
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0answers
161 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 ...
1
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0answers
110 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
160 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
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2answers
412 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
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1answer
87 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
82 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 ...
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0answers
74 views

How To Add a QgsSvgMarkerSymbolLayerV2 to VectorLayer in Qgis?

I'm using Qgis2.4.0 API to develop a C++ application. I want to add a svg symbol to a vector layer. Here is what I have already done: add vector, then add symbol. But I get stuck dong this. Here is my ...
1
vote
2answers
234 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 ...
1
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0answers
87 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: ...
1
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0answers
437 views

Correct way to extract pixel data using GDAL. Current method gives repeated but changing value.

I am trying to open a spectral file and move bands of data from GDAL to OpenCV's Mat data structures. As of now I am just trying to make sure that I can correctly access each band using GDAL and pull ...
1
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0answers
21 views

change symbology of an graduated renderer in qgis

In my plugin(c++) I add a vectorlayer to map, then I change the symbology of the QgsGraduatedSymbolRendererV2 of this layer. After this I refresh the map with ...
0
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0answers
23 views

Write to FGDB in C++ code?

Anyone know the correct syntax for this? I'm a C++ beginner but experienced in GIS.. I'm guessing ofstream won't do it and am not sure what else to try. Never written to any sort of database in C++.
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0answers
55 views

compile QGIS-plugin for Windows: problem with gdal_i.lib version

While compiling my plugin for QGIS 2.2 there are no errors, but it ist still not loading in QGIS because of an dll error. (function not found) I think the problem is at the gdal version. The ...
1
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2answers
126 views

Projection for polygon intersection confined into one hemisphere?

I have polygons where each vertex is a (lon,lat) geographic coordinate. I want to find out if they intersect or contain each other. The polygons are guaranteed to never exceed a hemisphere (so they'll ...
0
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0answers
9 views

How to debug a QGis C++ plugin with Visual Studio 2008 [duplicate]

I have a plugin for QGIS 2.2 in C++ (legacy). I dont find how debugging this plugin, with Visual Studio 2008 (for evolution, etc.) Sorry for my bad english. Thanks you ! Paho
0
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1answer
121 views

Calculate tree cover over certain area from raster data

Last year Hansen et al. published Global Forest Change map as set of raster data available in TIFF format. Basically those are 30-meters resolution satellite images with pixel values ranging from 0 ...
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0answers
140 views

gdal read whole geotif band into vector

i have another c++ GDAL question. I try to read alle elevation data out of an GeoTiff file into a c++ vector so that i can get elevation at x,y like this: vector[x][y]. I also like to use this data to ...
0
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1answer
127 views

gdal_contour transparent contour as png

I started using the GDAL Library in a c++ project. It is a great library, but I am a bit stuck right now with different aspects of it. What is the best way to use gdal_contour in my c++ programm? ...
1
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0answers
39 views

C++ parser for OGC Filter Encoding 1.0

I'm developing a C++ application and I have to parse a OGC Filter in order to implement querying functionality on a metadata repository. Does anyone know any C++ library to parse OGC Filters? Thanks. ...
1
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0answers
69 views

How to rasterize a vector data with style

I want to make a utility in c++ which can rasterize vector data with some specified style. I know about gdal_rasterize. But the problem with it is, we cannot specify the style details. Do we have a ...
1
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0answers
118 views

GDAL C/C++ API and filtered pyramid tile generation

I have been tasked with adding functionality to an existing C++ developed toolset whereby a source dataset (typically a single GeoTIFF) needs to be split into tiles at various resolutions ('zoom' ...
3
votes
2answers
260 views

Fastest Way to Intersect Envelope with Multiple Feature Classes ArcObjects

I have the situation where I am doing a large number of intersections and I need to do them fast. The situation is I have a iMap with 1 or more layers and a series of envelopes, lots of envelopes. I ...
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0answers
67 views

ArcObjects: How to remove a custom layer?

How is a custom layer supposed to be destructed? I have a custom layer that implements drawing by overriding IActiveViewEvents::AfterDraw. The problem is that sometimes when the custom layer is ...
2
votes
1answer
318 views

Rearranging labels in screen to avoid overlapping

I have a map, with some icon over it. Every icon has a label next to it. When icons overlaps, labels are overlapped too. In this case, I want to move labels so they don't overlap anymore, with a line ...
0
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1answer
284 views

QGIS 2.0 Howto copy raster data from a QgsRasterDataProvider to an OpenCV matrix

I'm hacking the half day arround a problem and that I' thought it was simple one. I'm using C++ (QtCreator) QGIS 2.0 und openCV2 on an 64 bit Workstation runnig Debian Wheezy. The Application I try to ...
2
votes
1answer
1k views

Is it possible to query via bounding box in the Google Maps Static API?

We have a Qt program written in C++ to request wms tiles and display them. This works fine. Now we want to display imaginery from Google Maps and due to some restrictions in our program, we can't use ...
3
votes
1answer
171 views

How to refresh layers independently?

I'm writing a C++ application using QGIS API and I would like to improve the performance. I want to render 5 layers: one raster layer using gdal to load Bing/Google Map tiles 4 custom QgsMapLayer ...
1
vote
1answer
90 views

how to transfer from traditional GIS software developing to internet area

I am a GIS developer, formerly doing some secondary development with GIS software. I now want to obtain some internet-based GIS area in my career. Somebody advised me to first read some ...
3
votes
2answers
728 views

combine raster with another raster mask file - gdal

I have 2 rasters in GeoTiff format. One has all of the land and water and the other is a mask file that shows either 0 for water or 1 for land. I basically want my output to just have the land values ...
1
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2answers
158 views

Difference between OGRGeometry and Geometry in C++ and python

According to the documentation, there is a python version of OGRGeometry's C++ class (http://www.gdal.org/ogr/classOGRGeometry.html) which is http://gdal.org/python/osgeo.ogr.Geometry-class.html ...
-1
votes
1answer
297 views

Free border data and C++ code to display state/region borders with user-defined-colour areas?

Situation: What I really need cannot be shortly described in the title. We have a commercial application where geographical maps (borders only) are used or for selecting areas (input) or for colouring ...
0
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1answer
284 views

How to find nearest Lat/Lon to the given Lat/Lon from set of Lat/Lon values?

I have a set of lat/lon values and gps lat/lon value. I want to find nearest lat/lon value to the gps point from that lat/lon set. Is there any some formula or some other way so that i could ...
1
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0answers
90 views

Icon missing when adding custom combobox command to Toolbar

I have a custom command: class ATL_NO_VTABLE CSliceSelector : public CComObjectRootEx<CComSingleThreadModel>, public CComCoClass<CSliceSelector, &CLSID_SliceSelector>, ...
0
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0answers
51 views

How to calculate GPS coordinates of one location relative another location? [duplicate]

In location “A” I know longitude (lonA) and latitude (latA) (Altitude is 50m). Relative to location A I know the horizontal (p) and vertical (q) distances to location “B” (B’s Altitude is 0m). I want ...
2
votes
2answers
237 views

how can i set place mark with text in QGIS?

I want to mark a point in map and place text near it. I used QgsVertexMarker to mark point .As far as now i am using tool-tip to show text. but i need clean code to show my text on map. Following ...
1
vote
1answer
106 views

OGRFeature::DestroyFeature fails

I am using OGR to read features from a shape file; when the feature is destroyed I am getting an error 0xC0000005: Access violation reading location 0xffffffffffffffff. This secton of the code looks ...
3
votes
3answers
556 views

A linestring merger algorithm

I'd like to merge linestrings which touch, but do not cross. The linestrings share the same SRID and come from a PostgreSQL 9.2/PostGIS 1.5 database. Within the table I query are several line strings, ...
2
votes
1answer
273 views

how to remove and change qgsvertexmarker in QGIS using c++ code?

In QGIS following code is used to set marker at point A. QgsVertexMarker * marker = new QgsVertexMarker(mPlugin->iface()->mapCanvas()); marker->setColor(Qt::black); ...
0
votes
1answer
711 views

GDAL RasterIO grabbing memory

I have written an application in c++ to read LiDAR files and convert to various rasters using GDAL; this worked very well on small scale tests (47 LAS files) however, when used on a live task the ...
1
vote
2answers
348 views

Shapefile point coordinates to lonlat

I'm currently trying to parse a shapefile (http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf) with c++. While I have no problems parsing all the data I need, there is a problem with the ...
2
votes
4answers
985 views

Offline Python or C++ library for plotting locations on map?

I'd like to plot locations using longitude and latitude coordinates using Python or C++, is there a good library for such a task? I know that matplotlib is an option, I'm wondering if there are any ...
1
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0answers
48 views

start gdalbuildvrt from c++ plugin

I want to create a vrt from my plugin via gdal-tool. From OSGEO4W-Shell the command works. In my code i tried this: QString program = "gdalbuildvrt"; QStringList arguments; ...