GIS test (Intermediate)

Sample questions

5 sample questions from the GIS test, with the answers. Samples are taken out of the live test, so you will not meet these when you sit it.

1. Which spatial analysis overlay type retains only the area where two layers overlap, making it useful for identifying common regions between datasets?

   1. Clip
   2. Dissolve
   3. Union
   4. Intersection

   Answer: D. Intersection

   Intersection is the correct answer because it refers to the overlay operation that retains only the area where two layers overlap. The other options (Union, Clip, Dissolve) refer to different types of overlay operations with distinct purposes. Union combines all areas from both layers, Clip cuts one layer to the boundary of another, and Dissolve merges features based on an attribute.

2. Which of the following statements is true about ArcGIS Model Builder?

   1. Model Builder restricts models to be used only within the same project.
   2. Model Builder prevents users from modifying individual tool parameters after model creation.
   3. Model Builder allows you to save and reuse geoprocessing models as tools in the ArcToolbox.
   4. Model Builder requires all tools used in a model to be from the same toolbox.

   Answer: C. Model Builder allows you to save and reuse geoprocessing models as tools in the ArcToolbox.

   Model Builder in ArcGIS allows users to create, save, and reuse geoprocessing models as tools in the ArcToolbox. This enables automation and streamlines workflows. The other options are incorrect because Model Builder does not prevent users from modifying individual tool parameters after model creation, it does not require all tools to be from the same toolbox, and it does not restrict models to be used only within the same project.

3. Which of the following statements about the Web Mercator (EPSG:3857) projection is correct?

   1. Web Mercator (EPSG:3857) is a geographic coordinate system and is not used for web maps.
   2. Web Mercator (EPSG:3857) preserves area and is ideal for scientific analysis.
   3. Web Mercator (EPSG:3857) is suitable for displaying maps on the web but not for accurate area measurements.
   4. Web Mercator (EPSG:3857) is a projected coordinate system that is ideal for calculating distances.

   Answer: C. Web Mercator (EPSG:3857) is suitable for displaying maps on the web but not for accurate area measurements.

   Web Mercator (EPSG:3857) is a projected coordinate system commonly used for web mapping applications because it preserves shapes and angles locally, which makes it suitable for displaying maps. However, it distorts areas, especially near the poles, and is not suitable for accurate area measurements. This is a well-documented behavior of the Web Mercator projection.

4. Which of the following accurately describes the structure and functionality of a file geodatabase (.gdb) in ArcGIS?

   1. A shapefile (.shp) is a container that holds multiple datasets and supports versioning.
   2. A personal geodatabase (.mdb) is the preferred format for large-scale geospatial projects and supports advanced versioning.
   3. A file geodatabase (.gdb) is a container that holds multiple datasets, including feature classes, tables, and raster datasets, and supports advanced data management and versioning.
   4. A geodatabase can only be hosted on a server and cannot be stored locally as a file.

   Answer: C. A file geodatabase (.gdb) is a container that holds multiple datasets, including feature classes, tables, and raster datasets, and supports advanced data management and versioning.

   A file geodatabase (.gdb) is a container that holds multiple datasets, including feature classes, tables, and raster datasets, and supports advanced data management and versioning. Shapefiles (.shp) are not containers and do not support versioning. A personal geodatabase (.mdb) is an older format that uses Microsoft Access and has limitations on data size and complexity. A geodatabase can be hosted on a server, but it is not limited to that; it can also be stored locally as a file geodatabase.

5. A GIS analyst is attempting to calculate the area of a polygon in WGS84 (EPSG:4326) and is getting an incorrect result. What is the correct action to take?

   1. The coordinates should be converted to a spherical CRS to avoid distortion.
   2. The coordinates should be reprojected to Web Mercator (EPSG:3857) for accurate area measurements.
   3. The coordinates should be transformed to a projected CRS (e.g., UTM) before calculating the area.
   4. The coordinates should remain in WGS84 as it is the standard for area calculations.

   Answer: C. The coordinates should be transformed to a projected CRS (e.g., UTM) before calculating the area.

   Calculating area using a geographic CRS like WGS84 (EPSG:4326) is incorrect because it measures distances in degrees, not metres. This leads to inaccurate area calculations. To ensure accuracy, the coordinates should be transformed to a projected CRS that uses linear units, such as UTM, before performing area calculations.