All activities within Arcview are organized with a Project, which may consist of a number of Views, Tables, Charts, Layouts and Scripts (Scripts are programs in the Avenue language and this exercise does not include user-defined scripts). The functions of Arcview include: displaying coverages in a view, viewing the related attribute tables of these coverages, relating attribute tables using a key field, plotting charts to display spatial information, and creating layouts of the view and related tables and charts.
When ArcView is first executed, a new untitled Project window
is opened (click cancel when prompted to open a new view). This window
includes several icons marked Views, Tables, Charts, Layouts, and
Scripts.
This is the main Project window, which allows you to create new Views,
Charts, etc., or to open existing ones that you have already created in
that project.
Help! If you are lost and don't know how to do something, ArcView
has on-line help which is accessed by hitting the
symbol in the top right corner of the display window.
Now we will add the rainfall data if file reydata.txt. Click on the Project window and highlight the Tables icon. Click on Add. At the bottom where it says 'List files of type' change the dropdown menu to 'Delimited text (*.txt)'. Select the file named 'reyprecip.txt' and click OK. Now bring the View window to the front by clicking on it, or if it is hidden use the 'Window' menu. From the View menu select 'Add event theme'. In the X Field select UTME and in the Y Field select UTMN. Click on OK. This should show up on the bar in the legend portion of the View window. Click on the raised part of the box to the left of the theme reyprecip.txt to make a check mark to see the coverage displayed in the View window. These are locations of raingauges.
You can zoom in or zoom out from a portion of the View window using
or
. To zoom to the extent
of active Themes, use the
tool in the upper row of the tool bar. A Theme is active if its legend
bar in the View window appears raised.
By clicking the icon in
the View tool bar and then clicking on a map feature in the View you can
find out information about any feature in the active Theme (a display of
its record in the data table). If you click on a feature and don't see
the correct record displayed, check to see that the correct theme is highlighted
in the View window legend bar.
Report the coordinates of the rain gage that is furthest west in this set.
By clicking on the icon
you can unselect all records. By holding down the shift key and clicking
on a selected record, it will be unselected.
The data that you are examining are precipitation recorded between October 1992 and August 1993. The table contains summary data computed from data recorded hourly. The attributes of the data, shown in column in the data table, include the name of the station, the location in UTM north and east coordinates and precipitation totals for the entire period (in inches and mm) and for each month (in inches). You'll see that the values for one station are very small, suggesting an error that needs to be investigated.
The file reydem.asc contains digital elevation data on a 30 m grid for Reynolds Creek. It is in an ASCII export format. In a View window select the File menu Import Data Source. Select import file type as ASCII raster and click OK. Select the file name reydem.asc. Give the output grid the name reydem, selecting the folder where you would like the grid file to be saved. Respond NO to cell values as integer (This data is actually integer data, but it is generally better to treat elevation data as real). Respond YES to add grid as theme to the view. The digital elevation model theme named reydem should now be displayed. To show the watershed outline and raingauges with this, drag the legend bar for the digital elevation model (reydem) below that for the precipitation and outline themes. Dragging a theme is accomplished by clicking beside the theme symbol, holding down the mouse and dragging the box that appears.
Determine the elevation of each rain gauge. With the theme reyprecip.txt
selected (and no features selected )
choose Summarize by Zones from the Analysis menu. Pick
the field 'Name' to define zones and click OK. Pick the theme
'reydem' containing the variable to summarize and click OK.
Click CANCEL for selection of the statistic to chart. A table 'Stats
of Reydem Within Zones of Reyprecip.txt' is created. Since Reyprecip.txt
is a point theme, each zone is a point that can only have one elevation.
The table shows the elevation in four columns mean, min, max and
sum, with range and standard deviation 0. (If the field being summarized
had been a line or polygon theme then the concepts of min, max, range,
standard deviation and sum would have been non trivial). Edit this
table to clean it up. From the Table menu select Start
Editing. Fields (columns) may be selected by clicking on the
grey name at the top. Select and Delete (Edit/Delete Field) all fields
except 'Name' and 'Mean'. From Table/Properties set the alias 'elevation'
for the field 'mean'.
From the Table menu choose stop editing and save edits. Now join
this table to the reyprecip.txt table. First select the field 'name'
(by clicking on the grey name) in the table 'Stats of Reydem Within Zones
of Reyprecip.txt'. Then select the field 'name' in the 'reyprecip.txt'
table. Then choose Join from the Table menu.
You will see that the table 'Stats of Reydem Within Zones of Reyprecip.txt'
disappears and a new field (column) with the elevation data appears in
the table 'reyprecip.txt'. The table 'Stats of Reydem Within
Zones of Reyprecip.txt' has been joined to the table 'reyprecip.txt' using
the field 'name' as a key field. This join can be undone by choosing
Remove
All Joins from the Table menu. A table can be sorted by selecting
a field (clicking on the grey name) then clicking one of the sort buttons
for an ascending or descending sort. Sort the table by elevation and
report the name of the lowest elevation station.
Open a new view, by double clicking on the Views icon
in the project menu. Add the 17050103.shp theme to this view (
add theme button). From the View menu select properties
Click on Projection and select category UTM -1927, type Zone
11. Click OK to the projection dialog and OK to the View Properties
dialog. You should notice a shift in the orientation of the displayed
reaches, and that the coordinates in the top left are now UTM (100,000's
of meters) rather than latitude and longitude (~100 degrees).
With the 17050103.shp selected from the Theme menu select Convert to Shapefile. Give a new name (17050103utm.shp). Say yes to the dialog to save in rojected units. Say OK to the message about the converted shape not being added to the view.
Close the projected view (X at the top right) and open the first view
(with the basin outline, elevation and rainfall data). Add (
add theme button) the new theme 17050103utm.shp to this view.
The streams should match nicely with the watershed outline and topography.
Select the river network within the Reynolds Creek basin outline.
With the17050103utm.shp active (raised legendbar) choose Select
by Theme from the Theme menu. In the Select by Theme dialog
box, select features of active themes that Intersect the selected
features of Rcout.shp. Since Rcout.shp is a polygon shape
file this means that all reach segments which are within or intersect the
Reynolds Creek Basin will be selected.
Click New Set. You will see that all of the river reaches
that intersect the Rcout.shp are highlighted. Now with the17050103utm.shp
active (raised legendbar) and Reynolds Creek streams selected (Yellow)
choose Convert to Shapefile from the Theme menu. Provide
a name (reystreams.shp) for the new shapefile. You will see
that this comprises only the streams of Reynolds Creek Watershed.
To Edit Features of the Chart, select the Chart Edit tool
and then click on the feature you wish to Edit. You can change the nomenclature
of the legend and the chart title and location in this way.
If you hold down the shift key and highlight a second station in the
View or the Table, its data will be automatically added to the chart.
Here is a comparison between the P095 and P098 stations
Begin by selecting a view
and drawing a box to accomodate it. When you've drawn the box, a dialog
box will come up asking you to select the view to show in the box. Select
View1,
and you should see your view of Reynolds Creek show up.
You can add another object template to the layout using the right hand
side tool in the lowest row of the upper tool bar. Select the chart object
to add a chart. To connect the chart visually to the corresponding point
in the view using the draw tool
which is selected from the list of icons under the
button. When drawing the line you'll find that it automatically snaps the
end points of the line to the grid points shown in the Layout window. To
stop that happening, click off Snap to Grid in the Layout/Properties
window. In case you choose to add a scale bar (fourth icon down)
to your layout and get a grey bar that says 'Unknown Units: View 1' you
need to switch back to the view window and select properties from the view
menu. Then set the map units pull down menu to meters. When
you switch back to the Layout the scale bar should show units, which can
be adjusted by double clicking on it.
You can add text to a Layout using the
button. You can also draw points, lines, and polygons using
.
If you find that the lines you are drawing are not in quite the right locations,
use Layout/Properties and click off the "Snap to Grid" box. To change
the size of the text you've added, highlight the text and use Window/Show
Symbol Palette and the text icon to alter the text size. Text size
of 14 point is the default. Usually 24 or 36 point looks good in layouts.
Similarly, to change the line thickness use the same pallete and select
the Line icon. Line thickness of 1 is the default. You can
directly print your layout from the Layout window, or you can export the
layout as a Placeable WMF (Windows MetaFile) and then import it into MS
Word using Insert/Picture/From File so that you can add a commentary on
what you did on the exercise.
These materials may be used for study, research, and education, but
please credit the authors and the Utah Water Research Laboratory, Utah
State University. All commercial rights reserved. Copyright 2000 Utah State
University.