EATS4400 GIS Lab.4 & Assignment 2 Lab4 Conversion of Hardcopy Map to ArcGIS Map In this lab exercise you will have chance to go through the steps to convert hardcopy map into digital map for ArcGIS. Digitizing a map to create GIS database is a common task in GIS application. This exercise will enhance your understand of the concepts of data features and data model etc. introduced covered in lectures 3 and 4. The main objective of this lab therefore include: 1. Converting hardcopy map (scanned images) to useable GIS data. 2. Understanding and use of ArcGIS extension ArcScan. 3. Understanding and use of ArcGIS Greoreference function I. Introduction Through the long history people have collected vast amount of data and made maps, tables and documents out of it for various purposes. Although some of these data have been converted into digital format and small amount of them are even available on Internet, there are still lot of data are in hard formats. To convert these hard copied data into digital format will increate the value of the historical data. It is potentially a good area to invest for the future. Secondly, to bring the digital data up to a level of standard so that them can be maintained and used for future systems is also a concern of the current GIS community. As you have known from the course lectures, constructing GIS database will help you to understand the issues involved in use of digital data. Through this lab exercise you will get some exercise and sense of data format, data model, data accuracy etc. Since GIS utilize topology information, scanned images and maps are not ready to be used in GIS. Certain processes have to be followed to convert them into usable GIS format. These processes include: scan a map, georeference a map, vectoralize a image and create attribute links. II. main process The following parts shows the steps necessary to convert a scanned map to useable data. Please note that some of the steps have been completed for you. Part A: Using ArcScan for ArcGIS Read Chapters 1 to 2 of Using_ArcScan_for_ArcGIS.pdf and complete Exercises 1 to 2 of the
book. Part B: Georeferencing the scanned image You have been given a GeoTiff (a geographically referenced image of the county map) of the county. From the file, a shape file containing Control Points needed to Georeference the scanned file was created. Using the control points from the shape file, you will now georeference the scanned soil map. Step A :Georeferencing 1. Copy the data from the H:\Courses\geog4340\lab\lab4\Geo.tif, ControlPoints.shp and Lotlines.shp to your F drive. 2. Open ArcMap 3. Add the Georeferencing Toolbar (GT). Under View>Toolbars this is where all of your toolbars are stored. 4. Add ControlPoints.shp followed by the Geo.tif. A building pyramids screen will appear. Select do not build pyramids, this allows for the best resolution at all views. Say OK to projection violations 5. From Georeferencing dropdown menu select Fit to Display 6. Add control points to the raster file Click on the Add Control Points. Click on the corner of the raster first and then the corresponding control point. It will be necessary to zoom into the corners in order to correctly align the raster corners to the control point. Pay attention to that controlpoint1 is at top left corner, controlpoint2 is at top right corner. Be sure to match control point correctly. 7. Under Georeferencing, Rectify the image to save the georeferencing and create an output raster. 8. Add the new TIF file to map and remove all other layers. 9. Close Georeference Toolbar. Part C: Convert the scanned image to Vector Data Step B: Clean the Raster Now you are required to convert the raster image to GIS vector data, use the knowledge that you have learned from Using_ArcScan_for_ArcGIS_Tutorial.pdf to finish this exercise. 1. Add the ArcScan Extension Verify that the extension is active Tools -> Extension -> click on the ArcScan. Add ArcScan toolbar 2. Open ArcCatalog and navigate to your F drive and Lab folder. a. Click File -> New -> Shapefiles (Create one new shape files: scanline.shp) b. Import the projections from Lotlines.shp to each new shape file. Add the new shapefile to the maps
3. Right click the raster layer (TIF file) in the ArcMap Table Contents and click Properties from the context menu to display Properties dialog box. Change the symbology tab to only black and white by clicking on Unique Values. 4. If the Editor Toolbar is not active, add it. Under this tool bar Start editing. 5. On the ArcScan Toolbar Vectorization Drop Down: Show Preview Zoom into the image. This will show why you need to clean up the raster file. Currently there are polylines. In addition, the text(contropt 1, ControPt 2 ) are being vectorized. You need to check them out. You will need to do some more Raster Cleanup and remove the words. Remove Show Preview. 6. Using Raster Cleanup to remove unwanted cell from raster image (for example ControPt 1, ControPt 2) Select Raster Painting Toolbar from the Raster CleanUp Drop Down, then Start Clean Up Select Erase tool or Magic Erase tool to erase all cells that are unwanted cell. You need to Zoom in for greater accuracy as you remove the unwanted cell With a clean raster background save the file and stop editing Step C: Convert the Raster image to vector data 1. Go back to the Vectorization Settings ->Change Compression Tolerances to 0.1 then press apply and change Maximum line width value to 10. 2. From Vectorization Drop Down Generate Features 3. Chose scanline as the line layer to add centerlines to. And press OK. Now you have Convert Raster Image to Vector Data. 4. Once the data has been converted from raster to vector, a data check must be applied. Are the new data valid? You can Add Lotlines.shp to check if your new data are valid. Part D: Editing attribute table When you create your vector file, you need to add attribute to it. Right click the scanline.shp in the ArcMap Table Contents and click open attribute table. Click optitions and select add field, name it as attribute, and add attribute information to the new created vector file.
EATS4400 GIS Assignment # 2 Due 11:30PM, Wednesday. Feb. 21, 2007 Hand in your report to TA NO LATE ASSIGNMENTS WILL BE ACCEPTED!!! You do not need to use computer to complete the assignment. If needed you can explain the processes it would be used to reach your results. Answer the following questions: 1. Can you comment on the main differences between GIS and other systems such as image processing, visualization, statistical analysis (SPSS) and database management system? 2. What are the main differences between spaghetti and topological vector models? 3. Why one call topological data model as spatial relational data model? 4. What are the main tasks and processes involved in on-screen digitizing? 5. What are the main advantages and disadvantages of JOIN and RELATE attribute tables? 6. Name three types of topological relationships the ArcInfo coverage file maintains? 7. What are the topological relationships dealt in ArcInfo topological model? 8. Explain the following concepts in the context of topological model: Spatial information Topological information Attribute information 9. Explain the advantages of adding metadata in ArcCatalog? List at least FIVE typical sections (types) of metadata used in ArcCatalog. 10. Name the possible spatial relationships among points, lines and polygons that can be extracted using ArcGIS. Fill them in the table provided below
Points Lines Polygons Points Lines Polygons 11. In ArcInfo topological vector model, there are two different types of point entities. Please name them and explain what are the differences between the functions of these two types of points and how they are handled differently in organization of their attribute information? 12. Since single GIS system never provides enough functions for all purposes of applications, ArcGIS and many other systems provide options for users to expend the functions of ArcGIS to serve special purposes. Please name THREE different possible ways to make a specialized GIS. 13. What are the main functions of the following components of ArcGIS. ARCSDE ARCIMS ARCTOOLS ARCMAP 14. List the advantage of using ModelBuilder in ArcGIS. 15. Give one example to clearly describe how to use ModelBuilder in ArcGIS. 16. Create proper ArcInfo coverage attribute tables to keep the attribute information from the following map.
17. In the files you have created from the question 16, which table(s) do you need to check in order to find intersection of ARCS? How about contact of two soil types? 18. Design an ArcGIS process in flow chart to show how to create a table to show the density of rivers in each of Canadian Provinces (total length of rivers within each provinces / area of the province). You are assumed to have two vector maps: one arcs representing rivers and the other polygon map for provinces.