GIS Web GIS and Services 4 — Questions and Answers
Question 1: What is the main advantage of using vector tiles over raster tiles in a web mapping application?
- Smaller server storage requirements for imagery
- Client-side rendering allows dynamic styling and infinite zoom without pixelation (Correct answer)
- Faster server-side rendering of complex cartography
- Better support for aerial photography display
Correct answer: Client-side rendering allows dynamic styling and infinite zoom without pixelation
Vector tiles contain raw geometry and attribute data rendered on the client (browser), enabling dynamic style changes and smooth zooming without server re-rendering.
Question 2: Which OGC standard specifies how to access geospatial features through a RESTful API aligned with HTTP best practices?
- WFS 2.0
- OGC API – Features (WFS 3.0) (Correct answer)
- WMS 1.3.0
- WCS 2.0
Correct answer: OGC API – Features (WFS 3.0)
OGC API – Features (informally WFS 3.0) is the modern RESTful successor to WFS, using OpenAPI specifications and JSON by default.
Question 3: What is geoprocessing proxying in a web GIS deployment used for?
- Converting vector data to raster format
- Relaying client requests to a GIS server while hiding credentials and bypassing CORS (Correct answer)
- Generating elevation profiles from DEMs
- Caching WMS responses for improved performance
Correct answer: Relaying client requests to a GIS server while hiding credentials and bypassing CORS
A proxy server sits between the browser client and the GIS backend, hiding API keys, enforcing CORS headers, and potentially adding rate limiting.
Question 4: In GeoServer, what is the purpose of a 'workspace'?
- A temporary file storage area for uploaded shapefiles
- A logical grouping of data stores, layers, and styles for organizational management (Correct answer)
- A user permission level for accessing secured services
- A cache region for frequently requested map tiles
Correct answer: A logical grouping of data stores, layers, and styles for organizational management
GeoServer workspaces act as namespaces to organize related data stores, feature types, and styles, helping administrators manage large numbers of layers.
Question 5: What does the term 'geocoding' refer to in a web GIS context?
- Converting raster imagery to vector polygons
- Translating a human-readable address into geographic coordinates (Correct answer)
- Encoding geometry in GeoJSON format
- Projecting coordinates from one CRS to another
Correct answer: Translating a human-readable address into geographic coordinates
Geocoding is the process of converting an address or place name (e.g., '123 Main St') into latitude/longitude coordinates for map display or spatial analysis.
Question 6: Which cloud-based technology approach serves pre-generated map tiles from a CDN to dramatically reduce map server load?
- WFS on-demand rendering
- Static tile hosting / tile CDN caching (Correct answer)
- WPS batch processing
- Real-time WebSocket streaming
Correct answer: Static tile hosting / tile CDN caching
Serving pre-rendered tiles from a CDN means map images are cached geographically close to users, eliminating repeated server rendering and reducing latency.
Question 7: What is the primary function of the Esri ArcGIS Feature Service's 'applyEdits' operation?
- Exporting features to a shapefile
- Adding, updating, or deleting features in an editable layer via the REST API (Correct answer)
- Generating a static map image from a feature layer
- Synchronizing offline edits from a mobile device only
Correct answer: Adding, updating, or deleting features in an editable layer via the REST API
The applyEdits endpoint allows clients to send add, update, and delete operations in a single REST call to modify features in an editable Feature Service.
GIS Web GIS and Services 4
What is the main advantage of using vector tiles over raster tiles in a web mapping application?