qgis

问题 In PostGIS, Is there a way to calculate another point 50 miles away in different directions? Given a point, ('New York',-74.00,40.71), how do I calculate the following points? 1) 50 miles directly North 2) 50 miles 45% North East 4) 50 miles directly East 3) 50 miles 45% South West Update: It seems http://postgis.net/docs/ST_Project.html may be the solution. ST_Project('POINT(-74.00 40.71)'::geography, 80467.2, radians(45.0)) However, I need to reference the database record to do it. not hard

问题 I've been able to get ahead from this step: Building QGIS source code on Windows 7 - Not working I'm trying to build the latest QGIS(2.10.1) using Visual Studio 10 Express but getting these unresolved symbols while building "ALL BUILD". In the Cmake-gui I can see these variables as undefined: QWTPOLAR_INCLUDE_DIR and QWTPOLAR_LIBRARY . Build configuration is set to Release. I remember while building the solution itself it showed a couple failures. All the unresolved symbols start with Qwt in

问题 When trying to compile the latest version of QGIS ( https://github.com/qgis/QGIS ) I end up with the folowing erros on cmake-gui: Traceback (most recent call last): File "/opt/QGIS/cmake/FindPyQt5.py", line 34, in <module> import PyQt5.pyqtconfig ImportError: No module named 'PyQt5.pyqtconfig' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/opt/QGIS/cmake/FindPyQt5.py", line 37, in <module> import PyQt5.QtCore ImportError: /usr

问题 I am trying to compile QGIS in Visual Studio. I used OSGeo4W to download the packages, added Flex.exe and Bison.exe to my environment path. Downloaded QGIS Release 2.0, and launched a CMake-GUI with the option "Visual Studio 10". Then I configured my paths using the GUI tool. Then I hit configure and generate, and it worked. I looked in my directory and there were Visual Studio Solution files available for me. Then I hit "Build All" and I got the following output in the "Output Window"

问题 I am using QtCreator and QGIS 2.6 to build a standalone C++ application. The problem I am encountering is the project cannot find all the necessary header files. My .pro file looks lie the following: QT += core gui xml greaterThan(QT_MAJOR_VERSION, 4): QT += widgets TARGET = TestQgis2 TEMPLATE = app SOURCES += main.cpp #HEADERS +=YOUR HEADERS #FORMS += YOUR FORMS #RESOURCES += images/images.qrc win32:CONFIG(Release, Debug|Release) { LIBS += -L"C:/Program Files (x86)/QGIS Brighton/lib/"

问题 I am using QtCreator and QGIS 2.6 to build a standalone C++ application. The problem I am encountering is the project cannot find all the necessary header files. My .pro file looks lie the following: QT += core gui xml greaterThan(QT_MAJOR_VERSION, 4): QT += widgets TARGET = TestQgis2 TEMPLATE = app SOURCES += main.cpp #HEADERS +=YOUR HEADERS #FORMS += YOUR FORMS #RESOURCES += images/images.qrc win32:CONFIG(Release, Debug|Release) { LIBS += -L"C:/Program Files (x86)/QGIS Brighton/lib/"

问题 Traceback (most recent call last): File "D:/Study/qgis3/QGIS/cmake/FindPyQt5.py", line 34, in <module> import PyQt5.pyqtconfig ModuleNotFoundError: No module named 'PyQt5.pyqtconfig' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "D:/Study/qgis3/QGIS/cmake/FindPyQt5.py", line 37, in <module> import PyQt5.QtCore ImportError: DLL load failed: Found SIP version: 4.19 Traceback (most recent call last): File "D:/Study/qgis3/QGIS/cmake

问题 I want to partition a US state into 20 parts of approximately equal population. I can do this using, say, tracts, ZIP codes or another smaller geography. I'm looking for an algorithm to do the partitioning. It can be in any language or software (ArcGIS, QGIS, python, PostGIS, R, node). For grouping or clustering algorithms I've looked at like k-means, ArcGIS Grouping Analysis, etc. These do not seem to do what's needed, since they group based on the similarity of a variable don't partition

问题 I have created some tiles out of a very large raster using the Qtiles plugin in Qgis. I have saved them to a local directory on my computer, and now want to render them in a leaflet map using R. The addTiles function passes a URL, but doesn't seem to work with a local filepath. In a different post (How to render custom map tiles created with gdal2tiles in Leaflet for R?), Lauren recommends using a www folder inside the shiny directory. Firstly, I'm not 100% sure what is meant by that, and

问题 i was trying to use a QString in the QGIS Python Console. from PyQt4.QtCore import QString but it says: ImportError: cannot import name QString In my Python IDLE it works fine, but i know that QGIS brings its own PyQt4. What could be the problem here? And could i solve it? import PyQt4.QtCore PyQt4.QtCore.QString() and from PyQt4 import QtCore QtCore.QString() dosen't works anyway. I was thinking about to copy the QtCore4.dll from my own PyQt4 installation to QGIS, but QGIS uses QtCore.prl