Viewing Data with PCI Geomatica FreeView
FreeView from PCI Geomatica is a free data viewer which can
be downloaded and used to view NAIP imagery and other geospatial files. It will
open the near infrared band (Band 4), allowing the user to switch from a natural
color display to color infrared, for both Digital Ortho Quarter Quads (DOQQs)
and JPEG2000 Compressed County Mosaics (CCMs).
FreeView displays vector files (shapefiles) and will allow
the user to query the attributes for individual polygons. FreeView does not
allow the user to save a project – it does what its name implies – operates mostly
as a viewer.
Using FreeView
Load Data into the
Viewer.
Data can be added to the viewer in several ways. One
is to click the Open icon on the main
toolbar, or under the File dropdown
menu
Another method – necessary when adding imagery – is to use
the Add Layer Wizard. This option
will require the user to make band assignments. In the first window of the
Wizard, the user selects the type of layer to add.
To add a shapefile, select Vector; to add a natural color or CIR image, select RGB.
Both the .shp and .sid files can be selected in this window.
The Wizard will allow the selection of more than one file,
of different types, but they will not display in the view window. Both names
will appear under the Files tab, but
they will not be visible, and will not appear under the Maps tab.
Files will need to be added individually in order for them
all to appear in the Map View.
A vector layer appearing under the Files tab can be opened under the Maps tab by right clicking the file name below Vectors and selecting View.
When adding an image, the second screen of the Wizard
requires band selection. In the screen below, the bands were assigned for
natural color, as Red: 1, Green:2 and Blue:3.
In the next graphic, the bands are set for a CIR image, with
Red: 4, Green: 1, and Blue: 2.
To change the band assignments of an image already in the
view, right click on the individual band under the Maps tab, and change the assignment. In the graphic below, the
southwestern DOQQ in the view is being changed from CIR to natural color.
The procedure for loading a JPEG2000 image is exactly the
same as for a DOQQ.
This JPEG2000 has been set up to view as a CIR image.
Removing an image is done by right clicking on the image
name under either the Maps or the Files tab, and selecting Remove. The files need to be removed
individually.
Zoom in and out on
the Display
There are several Zoom icons in FreeView. From left, they
are:
- Zoom to Overview (square with arrows at the corners moving outwards); this zooms to the “whole page” view.
- Zoom Interactive (magnifying glass); draws a rectangle around the area of interest and zooms to it.
- Zoom In (Plus sign); zooms in after clicking in the view
- Zoom Out (Minus sign); zooms out after clicking on the view
- Zoom to 1 to 1 Image Resolution (magnifying glass with “1”); Moves to a 1:1 resolution at the cursor location.
Measuring on the Map
View
FreeView allows the user to measure lines and polygons, in
differing units. The measurement tool is at the far right of the toolbar.
Measuring an ellipse gives a result for the area and
perimeter.
Measuring a polygon also displays area and perimeter.
Measuring a line gives an azimuth in addition to the length.
Changing a Vector
Layer Display
There is no option to label features in the FreeView map
display.
The color of a shapefile can be changed by right
clicking on the file name. Select Color,
and choose a preset color
Selecting More
will open a color table, with the opportunity to create a custom color.
The line feature can be edited by right clicking the icon
for Default Polygon under the file
name. This will open the Style Selector.
Clicking on More,
and then on Advanced will open a
dialog box with the option to create different versions of the polygon. The
polygon in the example below was created in three parts:
§ The first step was selecting a dark brown color for the line, and
making the width greater than the default.
§ The second step involved clicking on the “+” sign to add a “part”, and selecting “2”. For Primitive, the selection Polygon-Filled was chosen. A fill color
(yellow) was selected.
The third step, shown below, began with adding a third
part. Primitive was set to Line Dotted, a width was selected, and a
light blue color was selected. This line is barely visible above the brown line
in the Preview box at the right of the screen.
Viewing a Vector
Layer’s Attribute Table
The Attribute Manager is opened by right clicking on
the file name under either the Maps
or Files tab
Clicking in the box next to a record, or onto a polygon in
the display, will highlight the record in the table and change its color in the
display.
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