Geog, IES 377/Cee 357 Exercise 5 Page: 1/6. GEOG, IES 377/CEE 357: An Introduction to Geographic Information Systems

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1 Geog, IES 377/Cee 357 Exercise 5 Page: 1/6 1. Introduction: GEOG, IES 377/CEE 357: An Introduction to Geographic Information Systems Exercise 5 Compiling Spatial Database: Getting the other data layers into ARC/INFO Due Dates: November 6, 2000 (Lab 301) November 7, 2000 (Lab 302) November 8, 2000 (Lab 303) November 9, 2000 (Lab 304) (Total of 20 points) You have completed the conversion of the landuse coverage into ARC/INFO and made it ready to be used (Table 1). There are still other data layers which are not yet in a usable form or not in your workspace (which you named as sitedata in Exercise 3. In this exercise, you will get the rest of the data layers listed in Table 1 into a usable form and into the workspace. NOTE: Please remember to read slowly and carefully and watch out for typos. Also, remember that command syntax can be examined by using the usage command at any Arc/Info module prompt. Table 1: Current Status of the Data Layers Data Layer Format Coordinate System Status Landuse Map Arc/Info UTM Done Road Map Arc/Info UTM Not in workspace Sewer Line Map Arc/Info UTM Not in workspace Soil Map Arc/Info Interchange UTM Not yet Stream Network Map Arc/Info Generate UTM Not yet 2. Your Exercise 5: 2.1 Copying the sewer line and roads (existing ARC/INFO coverages): The road map and the sewer line map are already in the ARC/INFO format and in the UTM coordinate system. You can simply copy them over into your workspace. These two data layers are served over the network. Use ARC/INFO command COPY to copy these two data layers into your workspace. First, you need to be in your workspace (d:\sitedata). For copying the sewer line data layer, enter COPY s:\g377\lab5\sewers sewers at the Arc: prompt. To copy the road map, substitute sewers in the above command with roads. Use the listcoverages command to see if you have them in your workspace or use ARCPLOT or Arctools to display the coverages on screen. Use describe to obtain information about coverage sewers. You should study the information listed on screen carefully and also think about why we need this information. 2.2 Getting the soil data layer ready (ARC/INFO interchange format data): ARC/INFO interchange files normally would have.e00 as extensions. Often the data in ARC/INFO interchange format would already be in a usable form, which means that spatial topology has been built and attribute data have linked with spatial data. The data may have been projected into a known coordinate system. However, these may not be true all the times. So you should still check if the data

2 Geog, IES 377/Cee 357 Exercise 5 Page: 2/6 layer is usable yet by running the DESCRIBE command on the coverage after you have imported the data. The soil data layer in the interchange format is not yet in a usable form. You will perform the following tasks in this section to make it usable: a) import it into Arc/Info internal format; b) construct topology; 3) attach attribute data to it Importing from the ARC/INFO interchange format: Since the soil map layer of the area is in ARC/INFO interchange format, you need to import this data layer from ARC/INFO interchange format into ARC/INFO internal format. The command to import the data in the interchange format is IMPORT. Using the help system to find out more about this command. To import the soil data layer, enter IMPORT cover s:\g377\lab5\soils.e00 soils at the Arc: prompt. ARC/INFO should respond to you with Importing soils from interchange file s:\g377\lab5\soils.e00 Run DESCRIBE on the newly created coverage soils and you will find that the topology for the polygons is preliminary, which means that the spatial data have been changed since the last time the topology was built. This also means that you need to rebuild the topology (you will do it in Section below). If you enter LIST soils.pat, you will find that there are only four columns of data: Record ID (first column), AREA, PERIMETER, SOILS# (internal ID). This means that whoever created this soil data layer did not complete the job and you will have to enter the soil attribute data (such as soil type and suitability for construction) (You do this in Section 2.2.3) Constructing the polygon topology: As you have found out, the polygon topology of the soils data layer needs to be reconstructed. Let s now construct the topology of coverage SOILS. There are two basic commands for constructing topology: build and clean. We are going to use build this time. Type build alone at the Arc: prompt. The usage of build comes up. By now you should be comfortable with the syntax (synopsis) of the usage message. Since soils are represented by polygons we are going to construct polygon topology. Type build soils POLY and the computer will respond to you with the message of building polygons It will return you to the Arc: prompt once it is finished. You may be wondering what POLY is doing in the command build soils POLY. POLY here specifies that you are constructing polygon topology, which means that ARC/INFO will produce a PAT table (SOILS.PAT in this case) Getting soil polygon attributes in: You have learned how to get attribute data into ARC/INFO and link them with the spatial data in Exercise 4. The basic steps are: create an info table by defining the items (fields) needed, enter the attribute data into this info table, and finally link the info table with the pat table. Now let s put what you have learned in Exercise 4 into use. Table 2 contains the soil attribute information for the soil polygons. SOILS# is the internal soil polygon number created by ARC/INFO. The column labeled as SOILS-ID contains the polygon number (user defined polygon IDs), SOIL-CODE contains the names of soil types, and the fourth column (SUIT) contains the code indicating the suitability for construction. You may need to DEFINE (specifying item parameters width & output width can be the same as landuse.dat) a table in INFO and ADD and UPDATE records. After creating the table, and entering the data, link the soils attributes to the soil polygons! * Be careful to use the correct item to join SOILS.DAT and SOILS.PAT *

3 Geog, IES 377/Cee 357 Exercise 5 Page: 3/6 Table 2: A List of Soil Attributes SOILS# SOILS-ID SOIL-CODE SUIT Id Sg Id Id Ns Tn Sg Ns Id Tn Ns Ns Ns Sg Ns Ns Ko Sg Ns Ns Ns Ns Ns Sg Sg Ns Ns Ns Ns Ns Ns Sg Ns Id Id Ns Id Ss Ss Id Ns Ss 2

4 Geog, IES 377/Cee 357 Exercise 5 Page: 4/6 2.3 Getting the stream data layer ready (ARC/INFO Generate format): Importing from the ARC/INFO Generate format: The ARC/INFO Generate format is very simple (See the ARC/INFO on-line documentation on command GENERATE for detailed description). To import data in the Generate format, you need to run command GENERATE momentarily. To import the stream data layer, enter GENERATE STREAMS at the Arc: prompt. GENERATE has its own prompt and its own set of subcommands. You are now in the GENERATE subsystem (indicated by the Generate: prompt). To obtain a list of GENERATE subcommands, enter COMMANDS at the Generate: prompt. For now, you only need the INPUT, LINES, and QUIT subcommands. The INPUT subcommand tells the GENERATE subsystem where to read data. In your case, the subsystem will be reading the data s:\g377\lab5\streams.lin. Enter INPUT s:\g377\lab5\streams.lin at the Generate: prompt to tell the subsystem to read from the above specified file. At this point, the subsystem has not yet read the coordinates from the file. The LINES command tells the subsystem that it should read the data as linear features and should start reading the data right away. The subsystem responds with Creating Lines with coordinates loaded from s:\g377\lab5\streams.lin after you enter LINES at the Generate: prompt. Once the subsystem finishes reading the data, the Generate: prompt will return to you, which means that you have imported the data. Issue QUIT to leave the subsystem. You may want to use ARCPLOT or arctools to see the newly imported data layer. In order to register the imported streams data layer to any other data layers (such as ROADS and SEWERS) in the database, STREAMS must have the same tics as the other data layers. Since the STREAMS coverage is also in UTM, you can borrow the tics from ROADS. To do this, you need to use the GENERATE subsystem again. Issue GENERATE STREAMS, which will put you in the GENERATE subsystem for adding features to coverage STREAMS. At the Generate: prompt (indicator of being in the GENERATE subsystem), type COPYTICS ROADS. Once the Generate: prompt returns, type QUIT to exit from the GENERATE subsystem. Run DESCRIBE on STREAMS and study the information provided by DESCRIBE on this data layer. You should notice that the coordinate system for STREAMS is not known to ARC/INFO although we know that is in UTM and all other parameters are the same as those for the ROADS coverage. Issue the following commands to enter the coordinate information for STREAMS: projectdefine cover streams projection utm units meters zone 18 xshift yshift parameters You should study what these commands mean so that you will be able to use them properly in the future.

5 Geog, IES 377/Cee 357 Exercise 5 Page: 5/ Constructing streams topology: Constructing topology for linear features in ARC/INFO is not very different from constructing topology for polygon features. The only difference is that you specify LINE instead of POLY for the option of feature class type to be built. Here is the command to build topology for the stream data layer: BUILD STREAMS LINE. The other difference is that with the LINE option value, ARC/INFO will produce a AAT table (STREAMS.AAT in this case) instead of a PAT table Getting the stream attribute in: For the stream data layer, you are going to use a different way to get the attribute data into an info table (you may certainly use this method for importing attribute data into an info table for polygonal data layers). The attribute data for the stream data layer is stored s:\g377\lab5\streams.tab. That file is a text file which contains two columns (the first few records are shown in Figure 1). The first column contains the stream ID and second column contains the type (1 or 2) of stream. 1 refers to a major stream and 2 refers to a minor stream. Although the stream attribute data is in digital format already, it not yet in an info table format. First you create an info table containing two fields (items). The first item is used to contain the stream ID and second item is used to hold the stream type. Name these items STREAMS-ID and STREAMS- TYPE, respectively. Once you have created the info table, import the attribute data from s:\g377\lab5\streams.tab to the info table in INFO using the following command: add from s:\g377\lab5\streams.tab The computer should report 106 RECORD(S) ADDED after you have enter the above command. Use the LIST command in INFO to take a look of these records. Now you are ready to link the attribute data to STREAMS.AAT. You may want to review what we did in exercise 4 in order to execute this step. Up to this point, you have completed the compilation of a spatial database in ARC/INFO consisting of the following data layers: Landuse, Soils, Sewers, Roads, and Streams. You are set to perform some spatial analysis. 200,2 201,2 202,2 203,2 204,2 205,2 206,2 207,2 208,2 209,2 210,2 211,2 212,2 213,2 214,2 215,2 216,2 217,2 218,2 219,2 220,2 221,2 Figure 1: The First Few Records of the Stream Attribute Data

6 Geog, IES 377/Cee 357 Exercise 5 Page: 6/6 2.4 Printing the Data Layers Created in this Exercise: You have learned how to create a simple map in ARC/INFO in Exercise 4. Use similar ARCPLOT commands to produce a map for each of the new created data layers (use different map names for different data layers). 3. Questions: Write a one-paragraph summary of lab exercises. Be sure to include reasons for the procedures performed. 1) When you are creating the info table for the stream attribute data, why must you use the same stream ID name in the info table as that in STREAMS.AAT? 2) List the attribute definitions for each field used in the info table for holding the soil polygon attributes. Explain the reasons for defining the fields in such a way. 3) List and discuss some general steps (not Arc/Info commands) you would take to make a foreign data set, like a paper map, usable for your specific project. (Hint: What have we done so far?) 4. Things to Be Handed In: 1) Summary of lab exercises 2) Answers to the above questions and their supporting materials. 3) OPTIONAL A hardcopy of each of the four data layers created in this exercise OPTIONAL