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ArcView is the default Map Manager used in GeoWorlds. Users are refered to the ArcView
manual to obtain help information about ArcView's own features. Here, we will focus on the
features necessary to perform GeoWorlds map related tasks. These include accessing custom
GeoWorlds buttons added to ArcView's tool bar menu.
Following is the list of the most important questions asked when using the GeoWorlds
GIS Viewer component.
- How can I zoom in to (or zoom out from) a desired region in the map?
- How can I query the database for additional map layers covering the
desired region?
- How can I specify the geographic area associated with an Incident?
- How can I select a region of interest within the geographic area defined
by the Incident?
- How can I extract the place names associated with the region of interest
and export them to the Information Manager?
- How can I create buffers around the region of interest? (Note: this
feature is recommended for advanced users only)
Moving around the display
You can use the View button bar and tool bar in Arcview to move around and zoom in on
the display
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Zoom to full extent
Zooms to the full extent of all layers in a view. Click this button when you want
to be able to see everything in a view.
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Zoom to Active Layer
Click on a layer in a view's Table of Contents to make it active, and then click
this button to zoom to the area covered by the active theme.
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Zoom In
Zooms in on the center of a view.
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Zoom Out
Zooms out from the center of a view.
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Zoom In tool
Zooms in on the position you click or the area you define on a view.
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Zoom Out tool
Zooms out from the position you click or the area you define on a view.
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Pan tool
At any time, you can pan the view by dragging it in any direction with the Pan
tool.
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Having drawn the region of interest, click on the query button . If more
than one data warehouse is registered with the system, a dialog box with a list of
warehouses will popup. The system then queries the selected warehouse and downloads
information on layers intersecting the region of interest. These layers can then be
selected for display based on the |
.Show me! (link to AVI movie)
In the Incident Properties dialog box during the registration of the Incident, click on
the "GeoLocate" button to invoke the incident location dialog. You can specify
the location with as much detail as you have, though for locations outside the United
States, street address are ignored and the maximum resolution is at the city level.
Approximate locations in the form of relative distances from a known location are also
supported. For example, 100 miles south of Los Angeles, California OR 90 miles northeast
of Tokyo, Japan. In this case, the name field in the incident location dialog will have to
specify some label/name for the approcimate location.
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Pick the "Region Of Interest" drawing tool. Your cursor should
change into a crosshair type. Click on the view to define vertices of an arbitrary polygon
and double click to close the polygon. Tip: double clicking on a point in the view while
the "Region of Interest" drawing tool has been selected, will construct a region
enveloping the smallest administrative boundary that contains that point. This way rather
than drawing a region by clicking a polygon around, say California, we can double-click
any point inside the state of California to form a "Region Of Interest" exactly
equal to its boundary. |
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Selecting this button will pop up a dialog box showing all the layers
currently displayed on the map. You will need to select the layers (by clicking on the
name) you wish to export the names of geographic entities from. All names belonging to the
selected layers falling within the region of Incident are displayed. All or a subset of
the above displayed names can be selected for export to the Information manager component
of GeoWorlds. On clicking ok in the displayed dialog box, the GIS Viewer component asks
the user if they wish these selected names to be merged with previously exported names or
just replace the previously exported names. This is useful when building a large list of
names. As there is a limit on the number of names that Arcview will export, it is often
better to pick small regions at a time to export names from.
Note: Selecting a region which is likely to contain thousands of geographic entities is
not advisable as the extraction and export of this list of names would consume a large
amount of resources leading to unpredictable behaviour in the system. |
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- Select the "Create Buffers..." menu item under the "Theme" menu.
- In the dialog box, select the "Region Of Interest" as the name of the layer to
buffer, uncheck the "Use only selected features" checkbox and move to the next
step by clicking Next
- Select the width of the buffer specified in miles (default is 1 mile) and click Next.
- Select the option "Create the buffers so they are inside and outside the
polygon(s)"
- Elect to save the buffer in a new theme. You could leave the output filename at the
default value or change the path to a location of your choice. Make sure it does not
contain any spaces.
- Click on the Finish button to create the buffer.
- Activate the theme labeled "Region Of Interest" and delete it by selecting the
"Delete Themes" menu item under the Edit menu.
- Activate the theme labeled "Buffer 1 of Region Of Interest". Select the
"Theme Properties" menu item under the "Theme" menu and rename the
Theme to "Region Of Interest".
- At this point follow the directions given above to extract and export place names
falling within a region of interest.
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