The Land Use data can be used with TAP Area Coverage studies, as well as Path Profiles, Single-Point Field calculations, the Field Preview function and other TAP functions. The Land Use module enables you to find the land classification and apply it to many parts of TAP.

General Concepts

The USGS LULC files categorize land use in 200 square meter cells, with each cell assigned an attribute, such as Urban, Agricultural, Forest, etc. (For a complete listing of the categories and subcategories, see National Mapping Program Data Users Guide 4, Land Use and Land cover Digital Data from 1:150,000- and 1:100,000-scale Maps.) When the files are imported into the TAP format, TAP can determine the classification at a given set of coordinates.

In addition, TAP includes a Land Use Loss Database that correlates the land classification with a loss value as a function of frequency. When TAP is used for an area coverage study or single-point field calculation, the environment of the receiver location can be determined from the Land Use data, and a user-specified loss value can be applied. For example, if you want to include an additional loss of 3dB in your frequency band whenever a receiver location is in a forest area, and 6db when in an urban area, the Land Use Loss Database enables you to specify that condition. At the same time, you can specify a loss of 7dB for forest and 12dB for urban in a different frequency band. This approach gives you great flexibility in applying the effects of the land use information to your coverage studies.

The Land Use Loss Database also includes an option to specify an Area Type for the Okumura propagation model for each land use classification and frequency range. This enables the Okumura model to be much more adapted to the actual environment for a study in a given area.

Configuration

The TAP Land Use files are one-degree square areas, and follow a naming convention similar to the SoftWright topographic elevation data files.

For the Land Use files, the convention is

LwwwnnNW.LUC

Where

• www is the longitude of the SE corner of the degree area
• nn is the latitude of the SE corner of the degree area
• N is either N or S for the latitude direction
• W is either W or E for the longitude direction

To specify in TAP where the files are located, use the Land Use selection in the Configuration menu:

The Land Use Data File Path(s) form will be displayed:

Use the Add and Remove buttons to specify any path(s) where you install the Land Use files. The Diagnostics section reports several potential problems, such as a directory that does not contain any Land Use files, duplicate land use files in multiple directories, etc.

As with the TAP Topographic Data configuration, once this configuration has been specified, you will not need to open this form unless you need to make a change in where you want TAP to look for the files.

Land Use Loss Database

In order to associate loss values with the various combinations of frequency and land use categories, the Land Use Loss Database can contain numerous configurations, or "templates". Each template contains a set of loss values as a function of frequency and land use, and you can select which template to use for a particular coverage study.

The default templates supplied with the TAP Land Use Module are:

• FCC R&O 00-11 based on the FCC Report and Order in Docket 00-11, released in May 2000
• TIA TR8 (May 20, 1977) based on the Telecommunications Industry Association report of that date
• TIA TR8 (Revised) based on a proposed revision of TIA TR8

Note that these are representative samples only. You must verify the applicability of the Land Use Loss values based on frequency and land classifications that are most appropriate to your application.

The Loss Database Editor enables you to modify these templates, or to add your own. The editor is accessible from the Editors menu under Land Use data:

The Loss DB Editor form is displayed:

You can select the Template, and the Frequency Range in the pulldown lists near the top of the form, or create a new Template or Frequency Range with the New buttons.

In this example, note that some of the categories (51-54) have not been specified. In such cases, those land use classifications will be ignored in a coverage study.

You can also use the Loss Database Editor to specify the Okumura categories to associate with each land use category for each frequency range. The options are available in a pulldown list for the Area Type and Street Orientation columns:

The "Default for Study" option forces the program to use whatever default is set when the Okumura study is set up, ignoring the land use association.

Note that these are representative samples only. You must verify the applicability of the Okumura values based on frequency and land classifications that are most appropriate to your application.

As mentioned above, the Loss Database permits you to set up multiple templates for different conditions. For example, selecting another of the sample templates and finding a similar frequency range shows different loss values will be applied using that template:

Area Coverage Studies

To include Land Use data in an Area Coverage study, you must select the Advanced parameters by checking the "Use Advanced Settings" checkbox on the Area Coverage form:

Then click the More tab:

Mark the "Include Land Use Data" checkbox, and select the template to use. Note you can also inspect or edit the Land Use configuration using the Config button.

When the area coverage study is executed, the land use values will be included in the calculation of the field strength at each receiver location if the needed .LUC file for that area is found.

Path Profiles

To use the Land Use data with a path profile, click the Land Use button on the toolbar:

The Land Use form will be displayed and will show the land use classification and associated loss value of the location of the mouse cursor along the path.

This can be useful in getting a better idea of what the conditions are along the path, such as vegetation and man-made obstructions.

You can also use the USGS Land Use data as a guideline for creating TAP Surface Feature files.  The Land use data on the profile can give you an idea of the surface obstacles (vegetation, buildings, etc.) and you can create Surface Feature files to represent those obstructions.

Single Point Field

To include Land Use data in the TAP Single Point Field calculation, select the Surface tab. Mark the "Include Land Use Data" checkbox, and select the template to use. Note you can also inspect or edit the Land Use configuration using the Config button.

When the field calculation is performed, the land use classification is determined (if the .LUC files are available), and the loss value is included in the calculation:

Field Preview

You can include the Land Use data in the Field Preview function. Click the Field Preview button on the toolbar:

When the Field Strength Preview form is displayed, you can select the Land Use Loss Database template to use (or select "None" from the list). If the needed .LUC files are found, the Land Use data will be included in the calculations when you click on the map. The "More >>" button on the Field Preview form displays the field calculation details.

As shown in this example, the Land Use classification is found and the associated loss value is included in the calculation.

Map Window

When the Land Use data is to be used with the Map Window, you should first zoom in to the area of interest. When the Land Use function is initiated, the program will attempt to find all of the land use files for the current view of the map window. If the map is covering an area much larger than you need, additional time will be needed to find and open all of the files. Use the magnifying glass button to zoom into the area you want to consider:

When the Map Window displays the area of interest, click the Land Use Points button:

The Land Use form will be displayed. As you move the mouse around the map, the land use classification will be displayed:

If you select a Land Use Loss Template and specify a frequency, the loss value associated with the Land Use classification will also be displayed.

If you want to display colors for the Land Use classifications over an area, you can click the Land Use Area button:

The Land Use Data form for selecting an area will be displayed.

The default coordinate limits are the currently displayed map area. You can enter different coordinate limits, or you can double-click the coordinate boxes on the form to select an area with the mouse.

When you click the Search button on the area selection form, the program will find and plot the Land Use classifications.

You also have the option to check the Boundary box on the area selection form.

Checking this box will display a list of the objects contained in a boundary file. (You can select a different boundary file, even if it is not displayed on the current map.)

When you select an area object in the boundary file and click the Continue button, the latitude and longitude limits of that object are transferred to the Area Selection form:

If you click the Search button while the Use Boundary box is checked, the program will find and display the Land Use classifications inside the selected boundary.

You can also use the USGS Land Use data as a guideline for creating TAP Surface Feature files.  The Land use data on the map can give you an idea of the surface obstacles (vegetation, buildings, etc.) and you can create Surface Feature files to represent those obstructions.