It won't take a lot of modification to the steps above to do related calculations, such as calculating kWh/sq m values for each cell, and then get mean and/or median values of all cells within a polygon using the Zonal Statistics tool. If you want particular areas of the roof, you will need to have smaller polygons. El mismo ha tenido gran acogida por su facilidad de uso y mltiples funciones. Este programado es gratis y de cdigo libre. Official Training Manual Introduction to GIS Fundamentals Intermediate GIS with. O projeto nasceu em maio de 2002 e foi estabelecido como um projeto no SourceForge, em junho do mesmo ano. Tutorial de Quantum GIS 3.4 LTR Hemos realizado un tutorial mostrando funciones bsicas del programa de manejo de informacin geogrfica ( QGIS ). A very useful resource to get started using QGIS is this website. This will give you kWh potential per roof. PREFCIO Bem-vindo ao maravilhoso mundo dos Sistemas de Informao Geogrfica (SIG) Quantum GIS (QGIS) um Sistema de Informao Geogrfica de cdigo aberto. The online manual can be found here: and the exercise data can be downloaded here: A downloadable PDF version will be made available soon. You should end up with a vector layer where each polygon has an attribute representing the sum of all the raster cells intersecting the polygon. Check the boxes you want for each roof polygon, most importantly the "sum". Using the new raster and your building polygons, run the Zonal Statistics tool in the QGIS Raster menu. There is also a raster calculator in SAGA (available in QGIS Processing Toolbox) if you prefer it. You can then use the raster calculator in QGIS raster menu to create a raster where each cell has its kWh potential (the "/sq m" part of the noted "kWh/sq m" units is now represented by the cell size). If each cell is 0.1 sq m, don't forget to divide by 10 (or appropriate conversion based on cell size). Then figure out the math to calculate kWh per cell. If you are in the U.S., a state plane system may work, or else a UTM system could be appropriate anywhere.ĭetermine the units on the raster cell values. Units are in meters, but they are distorted as you move toward the poles. Pseudo-Mercator EPSG 3857 used by Google, OSM, websites, etc. Make sure you are working in a projection with appropriate units. If you need something finer, perhaps 0.316 m x 0.316 m would work to give you an area of ~0.1 square meters. It may be easier to do the math using a 1m x 1m raster size so each cell is 1 square meter, assuming this isn't too coarse for your evaluation. Generate the raster, as you have done (don't necessarily need to clip to polygons yet if you don't want to). I've not used the PV tool and don't know the units on the raster, but can give you a general idea for one way to accomplish this.
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