Upon performing the point-in-polygon overlay operation, a new point file is created that contains all the points that occur within the national park.
#Gis perform intersect with vector and raster plus#
The first step would be to acquire the point occurrence locales for the species in question, plus a polygon overlay layer showing the vegetation communities within the national park boundary. For example, suppose you were tasked with determining if an endangered species residing in a national park was found primarily in a particular vegetation community. In addition, all the points in the output layer contain their original attribute information as well as the attribute information from the overlay. Upon performing this operation, a new output point layer is returned that includes all the points that occur within the spatial extent of the overlay ( Figure 7.4 "A Map Overlay Combining Information from Point, Line, and Polygon Vector Layers, as Well as Raster Layers").
operation requires a point input layer and a polygon overlay layer. The point-in-polygon overlay An overlay technique that creates an output point layer that includes all the points occurring within the spatial extent of the overlay layer. The new layer produced following the overlay operation is termed the “output” layer. As you may be able to divine from the names, one of the overlay dataset must always be a line or polygon layer, while the second may be point, line, or polygon. Several basic overlay processes are available in a GIS for vector datasets: point-in-polygon, polygon-on-point, line-on-line, line-in-polygon, polygon-on-line, and polygon-on-polygon. Indeed, simply collecting and overlaying spatial datasets provides a valuable tool for visualizing and selecting the optimal site for such a business endeavor. Next, you may want to collect information on restrictions or roadblocks to development such as the cost of land, cost to develop the land, community response to development, adequacy of transportation corridors to and from the proposed mall, tax rates, and so forth.
After collecting and overlaying the baseline information on available development zones, you can begin to determine which areas offer the most economic opportunity by collecting regional information on average household income, population density, location of proximal shopping centers, local buying habits, and more. For example, you may first want to determine what areas can support the mall by accumulating information on which land parcels are for sale and which are zoned for commercial development. How would you attack this problem? With a GIS at your command, answering such spatial questions begins with amassing and overlaying pertinent spatial data layers. Figure 7.4 A Map Overlay Combining Information from Point, Line, and Polygon Vector Layers, as Well as Raster LayersĪ common example used to illustrate the overlay process is, “Where is the best place to put a mall?” Imagine you are a corporate bigwig and are tasked with determining where your company’s next shopping mall will be placed.
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