Navigation:  Productivity Tools (Tools Menu) > Import Shapefile

ESRI's .shp format, also known as "shape format" or "shapefiles," can be imported by BREEZE AERMOD. Shapefiles have been openly published by ESRI and are widely used for data interchange in GIS applications. Shapefiles usually consist of three similarly named files with differing extensions:

Main file: a spatial information file (.SHP),

Index file: an index file (.SHX),

dBase table: a dBASE file with attribute information (.DBF).

An ESRI shapefile consists of a main file, an index file, and a dBASE table. The main file is a direct access, variable-record-length file in which each record describes a shape with a list of its vertices. In the index file, each record contains the offset of the corresponding main file record from the beginning of the main file. The dBASE table contains feature attributes with one record per feature. The one-to-one relationship between geometry and attributes is based on record number. Attribute records in the dBASE file must be in the same order as records in the main file.

When importing a shapefile, only the .shp file is listed in the Open File dialog box. However, the .shx and .dbf files are required to utilize the data. Shapefiles as most commonly occur do not save projection information. Recent extensions to ArcView allow the saving of projected data in additional .prj files; however, most shapefiles that are published do not use this extension. Shape format is therefore best used to interchange data from unprojected drawings using degrees as the unit of measure. When such shape files are imported into BREEZE AERMOD 6, they will typically appear in Latitude / Longitude projection without any difficulty.

Serious difficulties can arise when people project drawings in other software and then save the resulting projected data as a shapefile. In such cases, there is no indication that the shapefile contains projected data and cannot be interpreted as a Latitude / Longitude map. Worse yet, there is no information contained within the shapefiles that specifies the projection and parameters used. If these are not provided within some readme.txt file or other accompanying documentation, the shapefiles lose their geographic context.

Since shapefiles cannot save datum information, try to find out what datum was used to save the data to the shape file and select that datum when importing the file. Failing to import a projected drawing from a .shp format correctly will lead to unpredictable effects when the drawing is used as a map. If you import a projected drawing from .shp, you must tell BREEZE AERMOD the correct projection to use to interpret that data since the format does not save this important information.

NOTE: In order to successfully open a shapefile, all three components of that shapefile must be present in the same directory (.shp, .shx, and .dbf).  An optional file with a .prj extension may also be present.

 

Base maps can also be imported and removed using the Map Manager tool.

To Import a Shapefile

There are two ways to launch this tool.

Step 1: Select the shapefile from local disk

Click the button and a file dialog box appears, choose the shapefile that you want to import to the project and click open. The shape file will be displayed in the Preview window

Step 2: Projection

Enter the projection and associated parameters of the shapefile being imported.

Step 3: Finish

Press the Finish button and confirm the shapefile was imported to the chosen display windows.

Adjustments to the imported image can be made in the Map Manager tool.  The Map Manager will allow you to remove the image from the project scenario.

 

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