Objective: The objective of this lab is to get you started with ArcCatalog, ArcMap and a little with ToolBox. You will: open shapefiles; measure distances; use the information tool; begin symbolizing data; examine and query data tables; sort tabular data; compute statistics from tabular data; select mapped features graphically; select mapped features from attribute characteristics in tables; select features by their location relative to other features; compute and use buffer zones.
The following data have been loaded into the class's resource page on Laulima. They can also be found on the cartography lab server (Odin) probably in \\odin\Data\Geog 488. When you download or copy the shapefiles, be sure to get all of the parts (.shp, .shx, .prj, .dbf etc.) of each shapefile.
oahucbpts.shp - Oahu census block centroid points (Census 2000) with various characteristics for the blocks, including urban/rural designation, population count and number of housing units. (It is missing the .prj file which you will need to create which you will need to set to answer several of the questions below. The Data are in unprojected WGS84 coordinates.)
allroad3.shp - streets and roads of Oahu, most with street names, address ranges, TMK zones. (Coordinates of the segment end points are also in the table, but it is the coordinates in the ".shp" that are used for drawing. Augmented and derived from Census bureau data.
cc-street.shp - City and County of Honolulu version of street segment centerlines and address ranges. Probably a better version than the allroad3 data.
soils.shp - Oahu soils from some NRCS source. Contains 4032 polygon records and codes soils into 163 categories.
streams.shp - Oahu hydrological features (shore, ditches, canals, streams, etc) from the USGS 1:24,000 Digital Line Graph (DLG) data, includes map edges from the 1:24,000 topographic quadrangle source maps and up to three major and minor code pairs indicating what the features are, as well as from- and to-nodes and area-left and area-right for the (within map sheet) topology. In the USGS Digital Line Graph (DLG) data, Major and Minor code pairs were/are used to numerically encode the kinds of things shown on printed topographic maps. For example, a major code of '50' means a 'hydrographic feature', and the minor code of '412' means a 'stream'. ) These (and more) codes are documented in the USGS DLG Data Users Guide, Circular 895C, available on the web (http://rockyweb.cr.usgs.gov/nmpstds/digstds.html - Part 3: Attribute Coding) and photocopied in the manila folders in the bookcase at the front of PSB 310).
One of the useful facilities of GIS software is the ability to integrate data from a variety of coordinate systems for use together. We'll spend some time examining this this term, but for now, know that map projection information for all but one of these data sets is in the associated .prj file and accessible via ArcCatalog or ArcMap as a general property of the data set. Those are distinct from the coordinate system used for the display panel (which you can access as a property of the display). This notion should make sense to you from Geog 104, 370 or 375. It will become clearer as we go.
To set a shapefile's coordinate system (.prj file): (1) Remove it from any project you have open. (2) Open ArcCatalog (the file cabinet icon). (3) navigate to the shapefile. (4) If it is in a directory to which you can not write, copy it to a directory where you can write --- your U: 'drive'. (5) On the X Y coordinate system tab / panel, select the system in which the shapefile's coordinates are recorded.
Help - is on the main menu of ArcMap, online from ESRI, and in the "Getting to Know ArcGIS" book.
Starting ArcMap - START:Programs:ArcGIS:ArcMap
Use ArcCatalog to connect ArcMap to your data folders. (And to associate coordinate systems with datasets that are missing them.)
Adding a shapefile to the map - Add layer; connect to folder; select files
Arrange layers - drag in legend
Hide (or Show) layers - check box in the legend
Tool bar tools - zoom in, out, previous, next, full; pan; identify; measure; select feature
Getting the table for a layer - left click name in legend, then choose "view table"
Properties of the display panel - right click in the body of the map (with the pointer tool?), and then go to the desired properties in the drop-down menu.
Symbolizing data - double left click the layer's name in the legend / table of contents. Under the symbology tab, you can symbolize a layer as one class, several classes (and by different strategies), or as unique values (individual symbols) using graduated colors and or sizes.
Selection - by location (for locating things that are in some spatial relation to other things, i.e. close-to, inside, intersecting, etc)
Selection - by attributes (use SQL-like query to select records from a table.
Statistics - calculate statistics (mean, minimum, maximum, total, standard deviation etc for (selected rows) of a column of data in a table) (when viewing a table, right-click on a column heading and select 'statistics')
Sorting in table - right click top of column.
Summarize - create a new table summarizing (mean, minimum, maximum, total, standard deviation etc) the values associated with unique values in a column in a table. When viewing a table, right-click on a column heading and select 'summarize'. Be sure that you are trying to write the table in a directory to which you have write permission.
Spatial Join - relates records from two tables based on the spatial relationships among the entities they represent.
Table Join - relates two tables based on matching values in key fields in each of the tables.
Map the data drive.
Start ArcCatalog and connect to the data folder using the "Connect to Folder" button and then browsing to the letter (F:?) selected above. You might as well make a connection to your home directory (U:?) now too.
Load the five data sets: oahucbpts.shp, allroad3.shp, cc-street.shp, streams.shp, and soils.shp into a new empty map (the Add-data "+" icon).
Spend a few minutes getting familiar with the controls. Pan, zoom, and drag to get around the image. Try the "back arrow" and "zoom to world" buttons. Use the check boxes in the legend to turn layers off and on. Change the colors on layers so they stand out better.
Examine the properties of the data layers (right click the name in the legend, the layer properties are accessed at the bottom of the drop-down list). In particular, note the symbology tab and the general tab where the coordinate system is specified.
Under the "General" (coordinate system) tab, find-out what coordinate system is used for each of the data sets. Are they all the same? Are any "Assumed"? Are any "Unknown"?
Under the symbology tab you can control the symbology used to
represent the layer. You can make (more) useful maps
by assigning more meaningful symbology to the features.
There are options for showing qualitative or quantitative
distinctions among, rather than just the existence of,
features in the layer based on data fields in the associated
We'll do more with this later, but for now, change these
symbolize the allroad3.shp street data so that all of the roads are red lines;
symbolize the census block populations (ratio level quantitative data) in oahucbpts.shp with small graduated circles whose sizes are proportional to the populations of the census blocks (POP100 field); and
symbolize the soil category (nominal data) with unique colors for each of the soil classes.
Open (and later close) the data table for each layer. See that the number of records is displayed at the bottom of the screen. Note the effects of clicking on a column label and on the box at the left end of a row. There is an "options button" at the bottom that gets you to the SQL interface to select by attributes, add new columns and do other things.
Check-out the interactive graphical selection tool. With it, click and drag over something in the map. Find the thing in the table. Try doing it from the table to the map. (There is a "zoom to selected" option that might help.)
Look at the properties of the display. (Right click in the map body.) See the coordinate system and options for reporting distance units?
Using ArcMap, answer the following questions. Some are easy; some are puzzlers. The objective is to get you thinking about how to put the component functions together to useful effect.