What are the advantages and disadvantages of using different coordinate system types in ArcGIS?

1 What are coordinate systems?

A coordinate system is a way of defining the location and shape of features on a map, using a set of rules and parameters. There are two main types of coordinate systems: geographic and projected. Geographic coordinate systems (GCS) use latitude and longitude values to describe the position of points on the earth's surface, based on a reference ellipsoid or spheroid. Projected coordinate systems (PCS) use mathematical transformations to project the curved earth onto a flat surface, such as a paper map or a computer screen, using units such as meters or feet.

2 Why are coordinate systems important?

Coordinate systems are important because they affect how accurately and consistently you can measure, display, and analyze spatial data in ArcGIS. For example, if you want to calculate the distance or area of a feature, you need to use a coordinate system that preserves the scale and shape of that feature. If you want to overlay or compare data from different sources, you need to use a common coordinate system that aligns the features correctly. If you want to visualize data in a meaningful way, you need to use a coordinate system that minimizes distortion and distortion and maximizes clarity and aesthetics.

3 What are the advantages of geographic coordinate systems?

Geographic coordinate systems have some advantages over projected coordinate systems in ArcGIS. First, they are simpler and more universal, as they use the same angular units (degrees) for any location on the earth. Second, they are more suitable for global or large-scale data, as they do not introduce any distortion or error in the representation of the earth's shape. Third, they are more compatible with some data formats and tools, such as GPS devices, web services, and geodesy functions.

4 What are the disadvantages of geographic coordinate systems?

Geographic coordinate systems also have some disadvantages over projected coordinate systems in ArcGIS. First, they are not very practical for local or small-scale data, as they do not account for the variation in the earth's surface and the effects of gravity and rotation. Second, they are not very user-friendly for mapping and analysis, as they do not reflect the natural perception of distance, direction, and area that humans have. Third, they are not very flexible for customization, as they have limited options for changing the orientation, origin, or extent of the map.

5 What are the advantages of projected coordinate systems?

Projected coordinate systems have some advantages over geographic coordinate systems in ArcGIS. First, they are more accurate and consistent for local or small-scale data, as they adjust for the distortion and error caused by projecting the earth onto a flat surface. Second, they are more convenient and intuitive for mapping and analysis, as they use linear units (meters or feet) and preserve some properties of the features, such as conformality, equivalence, or equidistance. Third, they are more adaptable and diverse for customization, as they have many options for choosing or creating the projection, the datum, the zone, and the parameters of the map.

6 What are the disadvantages of projected coordinate systems?

Projected coordinate systems also have some disadvantages over geographic coordinate systems in ArcGIS. First, they are more complex and specific, as they require more information and parameters to define and apply them. Second, they are more prone to distortion and error for global or large-scale data, as they cannot represent the curved earth without compromising some properties of the features. Third, they are more sensitive and dependent on the data source, location, and purpose, as they may not be compatible or suitable for different scenarios or applications.

7 How to check and change coordinate systems in ArcGIS?

To check and change the coordinate system of your data or map in ArcGIS, you can use various tools and methods. For example, you can use the Properties dialog box of a layer or a data frame to view or modify the coordinate system. You can use the Define Projection tool or the Project tool to assign or transform the coordinate system of a feature class or a raster dataset. You can use the Project Raster tool or the Warp tool to resample or reproject a raster dataset. You can use the Project On The Fly option or the Geoprocessing Environments settings to control how ArcGIS handles data with different coordinate systems on the same map.