Layer and Data filesLayer and Data files

What is a layer?What is a layer?

1. A set of vector data organized by subject 1. A set of vector data organized by subject matter – roads, rivers, or political boundariesmatter – roads, rivers, or political boundaries

2. A set of raster data representing a particular 2. A set of raster data representing a particular geographic area – aerial photograph or remotely geographic area – aerial photograph or remotely sensed image. sensed image.

3. A file that stores symbology and display 3. A file that stores symbology and display information for a given vector or raster data set. information for a given vector or raster data set. The layer does not actually contain the data, but The layer does not actually contain the data, but points to its physical location - points to its physical location - .lyr file .lyr file Definition based on 2001 ESRI Press – Dictionary of GIS Terminology

Def 1. A set of vector data organized by subject matter – Def 1. A set of vector data organized by subject matter – roads, rivers, or political boundariesroads, rivers, or political boundaries

Def 2. A set of raster data representing a particular Def 2. A set of raster data representing a particular geographic area – aerial photograph or remotely sensed geographic area – aerial photograph or remotely sensed

image. image.

3. A file that stores symbology and display information for a 3. A file that stores symbology and display information for a given vector or raster set. The layer does not actually contain given vector or raster set. The layer does not actually contain

the data, but points to its physical location. the data, but points to its physical location.

View In Arc Catalog View In Windows Explorer

The layer file (.lyr) does not actually contain the The layer file (.lyr) does not actually contain the data, but points to its physical location. data, but points to its physical location.

Saving your selectionsSaving your selections

11 Save as a temporary layer file Save as a temporary layer file (resides only in your project)(resides only in your project)

2.2. Save as .lyr file Save as .lyr file

3.3. Save as a data file (shapefile, Save as a data file (shapefile, geodatabase, etc…)geodatabase, etc…)

Creating a temporary layer Creating a temporary layer from Selected Features from Selected Features

Right click on the Right click on the layer in the TOClayer in the TOC

SelectionSelection Create Layer from Create Layer from

Selected FeaturesSelected Features

Saving Selected features layer Saving Selected features layer as a .lyr file or exporting as as a .lyr file or exporting as

data file data file

Exporting selected feature Exporting selected feature directly as data file directly as data file

Right click on the Right click on the layer in the TOClayer in the TOC

DataData Export DataExport Data

Summary of .lyr file and data Summary of .lyr file and data filefile

.lyr file.lyr file Selected features are Selected features are

NOT saved in a new NOT saved in a new data file.data file.

A .lyr file stores A .lyr file stores symbology and labeling symbology and labeling properties. properties.

Useful when you want Useful when you want to preserve the to preserve the symbology for symbology for consistency. consistency.

Saves disk spaceSaves disk space

Data fileData file Selected features are Selected features are

saved in a new data saved in a new data file (shapefile, file (shapefile, geodatabase).geodatabase).

Symbology information Symbology information is not stored in the data is not stored in the data file.file.

Selected features are Selected features are “permanently” saved. “permanently” saved.

Better performance. Better performance.