1. Geographic Information Systems (2017)
Map Projections
There are 3 different types of map projection. It is important to know the map projection being used because it can alter, and distort the map, maybe enough to make it inaccurate. The different map projections are :
Azimuthal Equidistant Projections: Projected as though it is on a flat piece of paper.
Conic Projections: projected as though a piece of paper is wrapped around the earth in a cone shape.
Cylindrical Map Projections: projected as though a piece of paper is wrapped around the earth in a cylindrical shape.
Introduction
Geographic Information Systems are maps with various data layers being showed, using one display. Throughout the 2 years working with GIS, you learn different techniques to making the map accurate and easy to read for viewers whom need information fast. There are many fields that use GIS, such as Government Agencies, Emergency Services, Homeland Security and even Health Care Professionals. GIS is mostly used for Urban and Regional Planning, with ties to the community and making sure that people are safe and accommodated for. People use GIS to find patterns and relationships between two different shape files, that may seem unrelated. Using the display box in ArcGIS, which is the program being used to create the maps, you can analyze and better understand the relationship trying to be shown easily, and precisely.
Types of maps
There are many different types of maps that can be created. What is important to remember while making a GIS is that it is easy to read, and covers not only one, but two or more topics of interest. A few of the most commonly created maps are climatic, Resource, Shaded Relief, Road, Topographic and Relative Location maps.
Climatic maps : Usually displays weather information like rainfall or temperature.
Resource maps: Provide locations of natural resources like oil, gas and coal. Depending on their entities, they use different content.
Shade Relief maps : Show change in elevation. Examples of this is mountainous areas, rivers, lakes, and ocean floors.
Road maps : Are used to show people how to travel from one place to another using physical features between places, such as major highways and smaller local roads.
Topographic maps: Shows change in elevation, using contour lines.
Relative Location maps: Shows location in relation to a feature’s surroundings.
Layers
ArcMap consist of not only one, but many layers to make a map that shows roads, elevation, streets, highways, and any selected features you are trying to bring attention to, all at the same time. All the layers are shown in the table of contents so that you are able to turn on and off the layers that you want and/ or don’t want.
Figure 01. Atlanta Georgia Military Installation compared to the location of nearby schools
Aerial Photography and Remote Sensing
Remote sensing is an observational view of an object, from a distance. When dealing with it in GIS terms, it refers to the study of the earth from a distance ( most likely an satellite image). There are two types of remote sensing; Passive Remote Sensing and Active Remote Sensing. Passive Remote sensing uses sensors and cameras that gather images using energy or light that is naturally reflected from the object to the ground, unlike Active Remote Sensing which uses electronically produced signals or light waves that bounce off targets. Aerial Photography is used to not only show shapes of desired areas, but thermal energy in the area, which can be useful depending on what it is being used for.
What to Include
There are 7 important items to include in every map that you make. The reason for this is that you want to make sure that the data you graphed is accurate, and reliable. You also want to easily know what is happening in the graph, and what is being graphed. The items you need to show are:
- Scale
- Title
- Symbols
- Legend
- Author
- North Arrow / Compass Rose
- Date
Figure 02. La Playa Community College Campus map.
Figure 03. Atlanta Georgia Base Map
Words to know
Ways Points: Locations or positions of landmarks or other points of interest that can be stored on a GPS unit.
True Color Image: An image that appears with colors that the human eye can detect.
Prime Meridian: Measured at 0 degrees longitude, is the starting point of the meridian.
Project Feasibility: Determined in terms of not only monetary costs, but also in terms of time, personnel, and material costs involved versus the potential benefit’s that will be received from conducting the study.
Project Management Model: A tool to lead GIS project managers through a set of steps, tasks, and techniques designed to help execute a thorough, successful geospatial project.
Project Stakeholders: Individuals, families, agencies, or organizations that have a keen interest in the project and /or the project findings or outcomes.