Intro to GIS

what GIS stands For?

GIS stands for Geographic Information System.

what we mean by Geographic Information?

- Geographic Information refers to data that is related to specific locations on the Earth's surface. It includes information about physical features, human-made structures, and other spatial data that can be mapped and analyzed geographically.

- it's not just about maps, but also about the data that describes the relationships and characteristics of those locations.

what are geographic approach 5 steps?

1. Ask: Define the problem or question you want to answer using geographic information.

2. Acquire: Gather the necessary geographic data and information relevant to your question.

3. Examine: Analyze the data to understand patterns, relationships, and insights.

4. Analyze: Use geographic tools and techniques to interpret the data and draw conclusions.

5. Act: Make informed decisions or take actions based on the analysis of the geographic

what's ArcGIS? portal? Maps and scenes? layers? analytics? apps?

- ArcGIS is a comprehensive geographic information system (GIS) platform developed by Esri. It provides tools for mapping, analyzing, and managing geographic data.

- Portal refers to the web-based interface of ArcGIS that allows users to access, share, and manage geographic information and resources.

- Maps and scenes are visual representations of geographic data. Maps typically show 2D representations, while scenes can include 3D visualizations of geographic features.

- Layers are individual datasets that can be added to maps or scenes. They represent different types of geographic information, such as roads, land use, or elevation.

- Analytics refers to the tools and processes used to analyze geographic data, uncover patterns, and derive insights.

- Apps are applications built on the ArcGIS platform that allow users to interact with geographic data in various ways, such as through web maps, mobile apps, or specialized tools for specific tasks.

what are 2 data models used in GIS?

- The two primary data models used in GIS are:

1. Vector Data Model: Represents geographic features using points, lines, and polygons. It is ideal for discrete features like roads, buildings, and boundaries.

2. Raster Data Model: Represents geographic information as a grid of cells or pixels, where each cell has a value representing a specific attribute (e.g., elevation, temperature). It is commonly used for continuous data like satellite imagery or digital elevation models.

there are 3 vector geometries. what are they?

- The three vector geometries are:

1. Points: Represent specific locations in space, defined by a pair of coordinates (x, y). For example, a city location or a tree.

2. Lines: Represent linear features that connect multiple points, defined by a series of coordinates. Examples include roads, rivers, and paths.

3. Polygons: Represent areas defined by a closed shape with multiple sides, formed by connecting points. Examples include lakes, parks, and land parcels.

what map in arcGis consist of? what's difference between basemap and operational layers?

- A map in ArcGIS consists of basemap, operational layers.

- Basemap layers provide a foundational geographic context for the map, such as satellite imagery or street maps. They are typically static and serve as a background.

- Operational layers are dynamic layers that contain specific data relevant to the analysis or task at hand. They can be updated, queried, and analyzed based on user interactions or data changes.

what is geoDatabase?

- A geodatabase is a database or file system used to store, manage, and analyze geographic data. It allows for the organization of spatial data in a structured format, supporting various data types and relationships.

- Geodatabases can be used to store vector and raster data, as well as attribute information, and can support advanced GIS functionalities like topology and network analysis.

what extension .gdb stands for? .shp?

- The extension .gdb stands for "geodatabase." It is used for file geodatabases, which are a type of geodatabase stored in a folder structure on disk.

- The extension .shp stands for "shapefile," which is a widely used vector data format in GIS. Shapefiles consist of multiple files that together represent geographic features, including geometry and attribute data.

what is web layer?

- A web layer is a type of GIS layer that is hosted on a web server and can be accessed over the internet. It allows users to view, query, and interact with geographic data without needing to download or store the data locally.

- Web layers can include various types of data, such as maps, imagery, feature layers, and scene layers, and are often used in web applications and GIS platforms like ArcGIS Online.

what are 2 main coordination systems?

- The two main coordinate systems used in GIS are:

1. Geographic Coordinate System (GCS): Uses latitude and longitude to define locations on the Earth's surface. It is based on a spherical model of the Earth and is commonly used for global datasets.

2. Projected Coordinate System (PCS): Uses a flat, two-dimensional representation of the Earth's surface, defined by a specific projection method. It is used for mapping and analysis at local or regional scales, allowing for accurate distance and area measurements.

every PCS is based on a GCS, and it transforms the spherical coordinates into a flat plane for easier analysis and visualization.

what's projection? and what is saptial distortion? what are 4 spatial properties subject to distortion?

- Projection is the process of transforming the three-dimensional surface of the Earth onto a two-dimensional plane, creating a map. This involves mathematical techniques to represent geographic features accurately.

- Spatial distortion refers to the inaccuracies that occur when projecting the Earth's curved surface onto a flat map. These distortions can affect the shape, area, distance, and direction of geographic features.

- The four spatial properties subject to distortion are:

1. Shape: The form of geographic features may be altered.

2. Area: The size of features may be exaggerated or reduced.

3. Distance: The space between features may not be represented accurately.

4. Direction: The orientation of features relative to each other may change.

mention some types of distortion and their effects?

- Some types of distortion and their effects include:

1. Equal Area Distortion: Preserves area but distorts shape and distance. Useful for thematic maps where area comparison is important.

2. Conformal Distortion: Preserves shape but distorts area and distance. Useful for navigation maps where angles and shapes are critical.

3. Equidistant Distortion: Preserves distance from a specific point but distorts area and shape. Useful for distance measurements from a central point.

4. Azimuthal Distortion: Preserves direction from a central point but distorts area and distance. Useful for polar maps or maps focused on a specific location.

what's default coordination system in ArcGIS?

The default coordinate system in ArcGIS is the WGS 1984 Geographic Coordinate System (GCS). It uses latitude and longitude to define locations on the Earth's surface and is commonly used for global datasets and web mapping applications.

when arcGIS automatically changes coordination system? when it converts the incoming coordination system to the current used one?

ArcGIS changes coordination systems automatically when you don't have any operation layer in the map andd add first operation layer. Any Added layer afterthat will be converted to that coordination system.

what's spatial analysis? what are different types of it? is it used separately always?

- Spatial analysis is the process of examining geographic data to identify patterns, relationships, and trends. It involves using various techniques and tools to analyze spatial information and derive insights.

- Different types of spatial analysis include:

1. Proximity Analysis: Examines the distance between geographic features to identify relationships, such as nearest neighbors or buffer zones.

2. Overlay Analysis: Combines multiple layers of geographic data to identify areas of overlap or interaction, such as land use planning or environmental impact assessments.

3. statistical analysis: Applies statistical methods to geographic data to identify trends, correlations, and anomalies, such as crime analysis or demographic studies.

4. Temporal Analysis: Analyzes changes in geographic data over time, such as tracking urban growth or environmental changes.

5. Network Analysis: Examines the connectivity and flow within a network, such as transportation systems or utility networks, to optimize routes or identify bottlenecks.

6. 3D Analysis: Analyzes geographic data in three dimensions, such as terrain modeling or volumetric analysis.

- These types may be used separately or in combination, depending on the analysis goals and the data available. Spatial analysis can be applied to various fields, including urban planning, environmental management, transportation, and public health.

what's difference between privilidges, roles and user types in ArcGIS?

- Privileges: These are specific permissions that define what actions a user can perform within ArcGIS, such as creating, editing, or deleting content. Privileges can be assigned to users or roles.

- Roles: A role is a collection of privileges that can be assigned to users. Roles help manage permissions more efficiently by grouping related privileges together. For example, a "Data Editor" role might include privileges for editing features and managing data.

- User Types: User types define the overall capabilities and access levels of users within ArcGIS. They determine the features and tools available to users based on their needs, such as Viewer, Editor, or Administrator. User types can include predefined roles and privileges tailored to specific tasks or workflows.

what 2 conditions we need to join 2 tables?

1. Common Field: There must be a common field (or key) in both tables that can be used to establish a relationship between the records. This field should have matching values in both tables.

2. Matching field data types in the key field.

what's difference between join and relate?

- Join: A join combines two tables based on a common field, creating a new table that includes fields from both tables. The result is a single table with all the attributes from both joined tables, allowing for direct access to related data.

- Relate: A relate establishes a relationship between two tables without combining them into a single table. It allows users to access related records in one table based on a key field in another table, maintaining the original structure of both tables.

what we mean by sharing packages? what are item types to share?

- Sharing packages refers to the process of creating and distributing collections of geographic data, maps, and other resources in a format that can be easily shared and used by others.

- The different types to share:

1. Layer packages: Contain one or more layers, including their data and symbology, allowing users to share specific datasets.

2. Layer files: Store the properties of a layer, such as symbology and labeling, without the data itself, enabling users to apply consistent styling to layers.

3. Map packages: Include a map document (.mxd) along with the data used in the map, allowing users to share complete maps with all associated layers.

4. Map files: Store the map document without the data, allowing users to open and view the map but requiring access to the original data sources.

5. Project packages: Contain all the resources needed for a specific GIS project, including maps, layers, tools, and settings, enabling users to share entire projects.

6. Project templates: Provide a starting point for new projects, including predefined maps, layers, and settings, allowing users to create new projects based on existing templates.

7. Web Layers: Allow users to share geographic data and maps over the web, enabling access to dynamic and interactive content through web applications.

8. Web Maps: Collections of web layers that can be shared and accessed through web applications, providing users with interactive maps and data visualizations.

9. Export: Exporting maps or layers to various formats, such as PDF, image files, or shapefiles, allows users to share static representations of geographic data. there's raster export like JPEG, PNG, TIFF, etc. and vector export like PDF, SVG, etc.