1. Geographic reference data: data describing the location and characteristics of spatial elements on the earth's surface, namely spatial data and attribute data. (P5)

2. Spatial data: data describing the geometric characteristics of spatial elements, which can be discrete or continuous; Attribute data: data describing the characteristics of spatial elements.

3. The difference between vector data and raster data: vector data is suitable for representing discrete elements, while raster data is suitable for representing continuous elements. Their structures are also different. The raster data model uses a row-column single data structure and fixed pixel positions. A vector data model can be geographically related or object-based, whether it has a topological structure or not, and can include single or composite elements.

4. The difference between geo-related data model and object-based data model: different storage methods. Geographically related models use different data systems to store spatial data and attribute data; The object-based data model stores spatial data and attribute data in a unified data system.

5. Tools and techniques for vector data analysis: buffer establishment (by measuring the linear distance of selected elements to create a buffer), map superposition (by combining the geometric shapes and attributes of different layers to create an output layer), distance measurement (by calculating the distance between spatial elements), spatial statistics (by detecting the spatial correlation and aggregation mode between elements) and map operation (by managing and changing the layers in the database).

6. Operation of raster data analysis: local (operation on a single pixel), neighborhood, partition (operation on a group of pixels with the same value or similar elements) and overall operation (operation on the whole raster). Mathematical functions are often used to connect input and output.

7. Exercise: ① Import raster files and Shapefile files into the geodatabase; (2) The method and process of generating slope map from ② grid file; (3) what file is *. Mxd and its function.

Chapter II Coordinate System

1. Importance of Geodetic Datum in GIS: Geodetic Datum is a mathematical model of the earth, which can be used as a reference or basis for calculating the geographical coordinates of a certain location. The definition of geodetic datum can include the origin of the earth, the parameters of ellipsoid used for calculation and the separation of ellipsoid from the earth at the origin. The concept of geodetic datum can also be used to measure altitude and height.

2. Map projection (transformation process from spherical earth surface to plane): systematic arrangement of longitude and latitude lines on the plane.

3. According to the reserved properties, four types of map projection are described: conformal projection, equal product projection, equidistant projection and co-directional projection.

4. Describe three types of map projection by projection or developable surface: cylindrical projection, conical projection and azimuth projection.

5. The difference between the standard line and the center line: the standard line is a commonly used parameter to define the map projection, which is directly related to the cutting state, and the standard line represents the pattern of projection deformation distribution; The centerline defines the center or origin of the map projection.

6. How to establish the relationship between the scale coefficient and the main scale: the scale coefficient is the ratio of the local scale to the main scale.

7. Universal projection coordinate system based on transverse Mercator projection: UTM-- Universal transverse Mercator coordinate system.

8. How to define UTM zoning by central meridian, standard meridian and scale coefficient: Each UTM zoning is drawn by Mercator projection of universal secant transverse axis, the scale coefficient of central meridian is 0.9996, and the latitude of origin is equator. The two standard meridians are 180km west and east of the central meridian respectively. The function of each UTM frequency band is to maintain the accuracy of at least 1:2500.

9. Exercise: Method and process of projecting latitude and longitude coordinates to horizontal Mercator projection.

Chapter III Geographic Relation Vector Data Model

1. Geographic relational data model uses an independent system to store vector data. The expression of "independent system" means that spatial data are stored in graphic files and attribute data are stored in relational databases.

Simple elements in 2.2. GIS and its geometric attributes: the dimension of a point is zero, only the attribute of location; The line is one-dimensional and has length characteristics; Faces are two-dimensional, with area and perimeter attributes.

3. Please describe how the data file structure of polygon coverage realizes the topological relationship of coverage model:

4. Expounds the importance of topology (connectivity, surface definition and adjacency) in GIS: ① It can ensure data quality; ② Topology can strengthen GIS analysis.

5. The main advantages of using Shapefile are: ① The display speed of non-topological vector data on the computer is faster than that of topological data; ② Non-topological data is non-exclusive and interoperable.

6. The partition in the partition data model is different from the polygon in the coverage model: the geographic partition data model can handle two spatial characteristics: ① a partition can be connected and separated in space, and ② a partition can overlap or cover the same area. However, polygons in the overlay model cannot handle these two features.

7. Exercise: ① ① What is the difference between the file structure of ①①Coverage and Shapefile? (2) The method and process of exporting ② coverage to Shapefile; ③ Methods and processes of importing and exporting ③Shapefile and dwg files.

The fourth chapter is the object-based vector data model.

1. Explain the difference between geographic relational data model and object-based data model: geographic relational data model stores spatial data and attribute data in different systems; The object-based data model stores spatial data and attribute data in the same system. An object-based data model allows spatial elements (objects) to be associated with a series of attributes and methods.

2.ArcObjects: A collection of objects.

3. As far as the geometric display of spatial elements is concerned, what is the difference between Geodatabase data model and Coverage model? Mainly lies in the composite elements such as partition and path. Geodatabase no longer supports sub-regions in the Coverage model, but the geometric features of sub-regions are still preserved by the geodatabase, because in the geodatabase, polygons composed of multiple elements can be composed of spatially adjacent or non-adjacent components, and can be superimposed on each other. The geodatabase data model of the path subclass in the Coverage model will be replaced by a polyline with the value of m (measured value). Geodatabases use m values instead of line segments and arcs to measure paths.

The relationship between 4.4. Geodatabases, feature datasets, and feature classes:

5. What is the difference between an independent feature class and a feature class contained in a feature dataset? Feature classes contained in a feature dataset are usually topologically related to other feature classes.

6. Definition of encapsulation rules in object-oriented technology: the technology of hiding the attributes and methods of objects so that users can only access objects through predefined interfaces.

7. Definition of polymorphic rules in object-oriented technology: The same method applied to different objects may produce different effects.

Advantages of 8.8. Geodatabase data model: ① It has new functional advantages of object-oriented technology; ② It provides a convenient framework for storing and managing different GIS data; ③ The complexity of coordination between spatial elements and attribute elements is avoided and the workload of data processing is reduced; ④ Objects can be customized according to the needs of all walks of life.

9. Exercise: the method and process of transforming Shapefile into Geodatabase feature class;

Chapter V Raster Data Model

1. Basic elements of raster data model: rows, columns and pixels.

2. Advantages and disadvantages of raster data model compared with vector data model: it is easier to operate, assemble and analyze data.

3. Give examples of integer raster data and floating-point raster data: integer raster data values have no decimal places and usually represent category data. For example, in the land cover model, 1 can represent urban land, 2 woodlands and 3 water bodies. Floating-point raster data with decimal places represents continuous numerical data. For example, the precipitation value of the precipitation raster data may be 20. 15, 12.23.

4. Relationship among pixel size, raster data resolution and raster representation of spatial elements: pixel size determines the resolution of raster data model.

5. Vectorization: Convert raster data into vector data. Including line thinning (only occupying a pixel broadband), line extraction (the process of determining the starting and ending points of independent line segments) and topological relationship reconstruction (connecting lines extracted from raster images and displaying digital errors).

Chapter VI Data Input

What kind of data does the 1.USGS DLG file contain? DLGs (Digital Linear Map) includes terrain (contour lines and elevation points), hydrology, boundary, traffic and American public land survey system. DLG is also a data format.

2. Describe the data types contained in SDTS topology vector standard file, point file and raster file: the topology vector standard file is for DLG, Tiger and other topology-based vector data; Point file supports measuring control point data; Raster files provide digital orthographic projection, digital elevation model and other raster data.

3. The working principle of differential correction: the method of correcting the noise error of GPS data with base station data.

4. What data must a text file contain before it is converted into a Shapefile?

5. The difference between point mode and stream mode in the process of digitization: In point mode, the operator selects points for digitization; In streaming mode, lines are digitized at preset time or distance intervals. If the digitized feature has many straight line segments, the point mode is the first choice.

6. Digital scanning methods include rasterization and vectorization. Why?

7. The source map has a great influence on the quality of digital map. For example, the source maps of USGS standard maps are second-hand data sources, because these maps have gone through a series of cartographic processing processes such as synthesis, synthesis and symbolization, and each process will affect the accuracy of cartographic data. For example, if there are errors in the editing process of the source map, these errors will be passed on to the digital map.

8. Suppose you were asked to convert a paper map into a digital data set, how would you do it? Advantages and disadvantages of each method:

Chapter VII Geometric Transformation

1. Map-to-map conversion: The unit of new digitized map is based on digitizer, whether it is manual digitization or scanning digitization tracking. Digitizer units can be inches or dots/inch. This geometric transformation process from a new digitized map to projection coordinates is called map-to-map transformation.

2. Image to map conversion: The rows and columns of satellite images are converted into projection coordinates.

3. Affine transformation can be rotated, translated, tilted and unevenly scaled. Describe various transformations: rotation refers to rotating the X axis and Y axis of an object at the origin; Translation refers to moving the origin to a new position; Tilting refers to the existence of non-vertical angle or affine angle between axes, which makes its shape become parallelogram in the oblique direction; Uneven scaling refers to increasing or decreasing scaling in the x direction or the y direction.

4. Three steps of affine transformation: ① Update the X and Y coordinates of the selected control points to real-world coordinates. If it cannot be updated to the real world coordinates, it can be obtained by projecting the latitude and longitude values of the control points; ② Run affine transformation on the control points and check the RMS error. If the RMS error is higher than expected, please select another series of control points and run the affine transformation again. If the RMS error is within the acceptable range, the six affine transform coefficients estimated by the control points will be applied to the next step. ③ Calculate the X and Y coordinates of digital map elements or image pixels with estimation coefficients and transformation equations.

5. The role of control points in affine transformation;

6. How to choose the ground control points for map-to-map conversion: only the points with known real-world coordinates are needed. If not, you can project points with known latitude and longitude values into real-world coordinates. For example, the USGS standard map with the scale of 1:24000 has 16 points with known latitude and longitude values, which are also called geographic control points.

7. How to select ground control points from image to map: directly select from satellite images. The real world coordinates of ground control points can be obtained by reading digital maps or GPS.

8. Root mean square (RMS) error in geometric transformation: In geometric transformation, RMS is a statistical method to estimate the deviation between the actual position and the estimated position of control points.

9. Why do you need to resample the pixel values in the process of image to map conversion? The result of geometric transformation of satellite image is a new image based on projection coordinate system, but this new image has no pixel value, and the pixel value must be filled by resampling.

10. Try to describe three common methods for resampling raster data: adjacent point interpolation (fill the nearest pixel value of the original image with each pixel of the new image. Its advantages are high calculation speed and retaining the characteristics of the original pixel value. ), bilinear interpolation (giving the average of the four nearest pixel values based on cubic linear interpolation to the corresponding pixels of the new image) and cubic convolution interpolation (finding the average of 16 adjacent pixel values by quintic polynomial interpolation). Both bilinear interpolation method and cubic convolution interpolation method are to fill the distance-weighted average of pixel values in the original image into the new image. The latter is smoother than the former, but it takes longer processing time.

1 1. For type data, it is suggested to resample by adjacent point interpolation. Reason: Adjacent point interpolation method can retain the characteristics of the original pixel value.

12. What is the pyramid method? Common methods for displaying large raster datasets. Large meshes with reduced resolution are represented by establishing different pyramid levels.

Chapter VIII Spatial Data Editing

1. The difference between positioning error (geometric error of digitized elements) and topological error (affecting GIS software packages or user-defined topological relationships):

2. Try to describe the difference between hanging nodes (points that are not completely combined at one point and generated at the end of hanging) and pseudo nodes (points that appear on a continuous line segment and unnecessarily divide the line segment into several segments): hanging nodes are acceptable in some special circumstances, while some pseudo nodes are not.

3. Map topology: A temporary collection of topological relations between elements that are regarded as coincidence. Layer types can create shapefile files or geodatabase model features, but they are not Coverage.

4. Describe three basic steps of applying topology rules: ① Create a new topology by defining the types of participating elements; ② Verification of topological relations; ③ The verification results will be stored in a topology layer to correct errors and accept them under special circumstances.

Chapter 9 Input and Management of Attribute Data

1. Element attribute table: an attribute table for storing element space data.

2. Distributed database system:

3. Describe four types of attribute data based on the concept of measurement scale: nominal data, ordered data, interval data and ratio data.

4. Relational database: a collection of tables related by keywords.

5. Advantages of relational database: simple and flexible. ① Each table in the database can be compiled, maintained and edited separately from other tables; (2) These tables remain separate until they need to be connected due to query or analysis.

6. Merge operation (* * * of the two tables have the same keyword to connect the two tables together. Similarity and difference between merged tables and attributes can be used for data query and data analysis) and association operation (only connecting two tables together temporarily, while each table remains independent).