The dBase file is very similar to a sheet in a spreadsheet and can even be opened in Excel. This is a dBase file which contains the attribute data for all of the features in the dataset. This file contains the geometry of each feature. It’s not important that you remember what’s in each part of of a Shapefile, but I think a brief explanation will help you better understand how GIS data is structured in general. The name Shapefile is a little deceptive because the file is made up of at least four parts. It’s a vector format that can be read by almost all GIS systems. The Shapefile is the most common format in GIS. This format is usually used for satellite imagery, aerial photography, elevation models and topographic maps. Raster data is a bitmap image such as a TIFF or JPEG. If vector data is abstract, raster data is literal.
#RASTER FILE FORMATS GIS HOW TO#
That column contains one or more coordinates that describe how to draw the point, line or polygon that represents that feature on the face of the earth. The best way to visualize it is to think of it as a spreadsheet with columns that contain your regular data, but in addition it always has an extra column called “geometry”. You can think of vector data as instructions for how to render data. Primarily there are two main types of GIS data: vector and raster. There are a dizzying array of formats used for storing GIS data.īefore we delve into the various formats let’s take a look at some fundamentals. If you think the term GIS is vague, then you haven’t seen anything yet. But first you need to take a crash course in GIS data.
Now we understand what a GIS is and what is can do, the next step is to understand how a GIS is made.
Beginner's Guide What is GIS? GIS Mapping GIS Data GIS Software Web GIS
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