ArcGIS – ESRI Questions & Answers

ArcGIS – ESRI Questions & Answers Describe the difference between a paper map and a GIS map - ✔✔GIS maps are dynamic You can manipulate the features of a GIS map, you cannot change the features of a paper map This inc ...

ArcGIS – ESRI Questions & Answers Describe the difference between a paper map and a GIS map - ✔✔GIS maps are dynamic You can manipulate the features of a GIS map, you cannot change the features of a paper map This includes zoom, selecting features you wish to see, and access a database for more features How is a GIS map organized? - ✔✔A GIS map consists of 1 or more dataframes A data frame is a collection of layers A layer is a collection of features A feature represents a real-world object What is a feature? 3 ways they are represented? - ✔✔Features are geographic, real world objects Represented as point, line, or polygon What is a point? A line? A polygon? - ✔✔Point = one coordianate pair representing a location on earth's surface Lines = two or more coordinate pairs Polygon = composed of one or more lines whose starting and end coordiante points are the same What is an attribute? - ✔✔Information that is associated with a feature other than its shape and location Linked by FID What does scale mean in GIS? - ✔✔Scale is a ratio One unit on your map represents X units in the real world What is ArcMap? - ✔✔It is a program used for visualising, editing, and analysing geographic data and can produce map products (data and layout views) What is ArcCatalog? - ✔✔It is a program used for accessing, browsing, managing, and storing data What is ArcToolbox? - ✔✔It is an organized collection of tools for GIS analysis, data management, data conversion, and so on. What is metadata? - ✔✔It is data about data; it is information that describes or documents a geographic dataset Is Earth vertically or horizontally squashed? - ✔✔Vertically What are four basic types of spatial relationships? - ✔✔Distance Containment Intersection Adjacency What are six things GIS can do with data? - ✔✔Capture Store Query Analyse Display Present What are symbols for? - ✔✔Symbols are assigned to features and symbolize these features based on attributes associated with that feature What three things do you need to decide when symbolizing features based on quantities in ArcMap? - ✔✔How many classes to have What method to use for placing the values into classes What kind of symbology to use What are natural breaks (Jenks)? When should you use it? How many classes should you use? - ✔✔Identifies groupings of values that are inherent to your data Use when attributes are distributed unevenly across the overall range of values For classes, choose a number that best reflects the natural groups of attributes you want to show What are equal intervals? When should you use it? How many classes should you use? - ✔✔It is similar to a ruler, with an interval between each class is equal Use when you want all classes to have the same range For classes, choose a number that produces an easily understood interval (2, 5, 10) What are quantiles? When should you use it? How many classes should you use? - ✔✔Each class contains an equal number of values (features) Use when attributes are evenly distributed in a linear fashion For classes, choose what makes the most sense What are manual? When should you use it? How many classes should you use? - ✔✔Each class has a range that you specify Use when you want classes to break at specific values For classes, choose what makes the most sense What classification scheme should you use? - ✔✔The fewer classes, the better Two ways you can map density using attribute values? - ✔✔One way is to divide the attribute values by the area of each polygon feature (i.e. data normalisation) Another way is to do so visually by using symbology to represent quantities of things in the real world (like a dot density map) What are two types of coordinate systems? - ✔✔Geographic Projected What is a GCS? What is it measured in? - ✔✔A GCS is used to locate objects on the curved surface of the earth, attempts to model the shape of the earth as accurately as possible DMS What is a PCS? Based on what? Where is the origin? - ✔✔A PCS is used to locate objects on a flat surface (GIS map on computer screen) Cartesian Origin at (0,0) in the middle of the map What are lines of longitude called? Latitude? What angles are they measured at? - ✔✔Longitudes are meridians and latitudes are parallels Longitude coordinate represents a line at the prime meridian and a line extending east along the equator Latitude coordinate represents a line on the equator and a line extending north along the 60 meridian What are two shapes commonly used to model earth? What shape does Stark think it is? - ✔✔Sphere (best for small scale) Spheroid (best for large scale, Stark thinks earth is spheroid) What is a datum? - ✔✔A datum is used to align the spheroid with the surface of the earth, it specifies which spheroid you are using as your earth model and at which exact location you are aligning that spheroid on earth's surface What does a datum define for GIS? - ✔✔It defines the origin, or the point where the spheroid matches up perfectly with the surface of the earth and where the latitude-longitude coordinates are true and accurate; all other points are in reference to the origin All geographic datasets have GCS but not PCS (T/F) - ✔✔TRUE ArcGIS can perform an on the fly projection if the PCS does not match with other layers (T/F) - ✔✔TRUE What are three types of surfaces that can be projected on to a map? - ✔✔Cylinder Cone Planar Where is a cylinder projection most accurate? What kind of maps can you produce? - ✔✔Most accurate in equatorial zones Produces maps with straight, evenly spaced meridians and straight parallels that intersect meridians at right angles Where is a cone projection most accurate? What kind of maps can you produce? - ✔✔Most accurate in mid-latitude zones Produces maps with straight converging longitude lines and concentric circular arcs for latitude lines Where is a planar projection most accurate? What kind of maps can you produce? - ✔✔Most accurate at the poles Produces maps on which the longitude converge at the north pole and radiate outward, latitude lines appear as a series of concentric circles What are the four spatial