From the course: Creating Maps with R

GIS data formats: Raster or vector

From the course: Creating Maps with R

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GIS data formats: Raster or vector

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- [Instructor] GIS data comes in two completely different flavors, vector or raster. You need a completely different workflow for vector and raster GIS data sets. Fundamentally, they're stored in different formats, which means different file types. You need to analyze or wrangle these data sets differently, which means different R packages. And finally you'll use completely different data visualizations to communicate information about these data types. There are three things I need you to take away with this video. An understanding of why rater and vector data sets are different. An ability to tell when data has to be vector or raster. And finally, you'll need to be able to understand which type of data you have. So we can better understand the formats. Let's imagine two cell towers or radio masks and how to range of these towers overlap. This problem can be represented in either vector or raster world. In the vector GIS world, the range of our masks is the perfect circle. This means that we can also precisely calculate the area that they overlap. Similar to how a Venn diagram works. Whereas in a raster world, everything is represented as a grid. This means that calculating overlaps always results in an overestimate of the true area. Vector GIS data sets are composed of points and or lines. We use vector GIS to represent precise locations and use them for creating geo scatter plots. We also need to use vector GIS data sets to create choropleth, as the only way to represent country or any geospatial boundary is with a smooth line. Now let's think about raster GIS data sets. Data is always represented as a grid but not necessarily a rectangular grid. Raster data is a consequence of how the data was first collected. Satellite imagery is a perfect example, very sensitive cameras image. The surface of the earth and a data quality is directly related to the resolution of the original image captured. Weather data is also rasterized because we can only measure weather conditions across a grid of weather stations. We then interpolate values between these measurement points. For the majority of folks wanting to make maps the data sets, it's vector GIS data that you'll be working with, and that you're required to make your data visualizations. Raster data can be considered specialized as it's almost always collected by specialized implementation.

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