SVWebsite

by Girish Madan, .NET Developer

Introduction

When working with ArcMap, it is inevitable that you will want to look through layers and see how they overlay on top of the layers underneath. ArcMap allows this by providing Transparency, Brightness and Contrast settings based on the type of layer e.g. Feature Layers have only the Transparency setting while Raster Layers have all the three settings available to them. These settings can be accessed through the Display tab in the Layer Properties window. Changing the appearance of one or two layers once in a while this way is fine but imagine changing these settings for multiple layers numerous times a day. A simple chore becomes a nightmare if needs to be repeated again and again.

Spatial Vision has developed a handy tool called Layer Transparency which has made this task readily available at the click of a button. It allows you to change the visibility, transparency, brightness and contrast of various layers in an easy to use form. The changes can either be made in bulk and then viewed on the map or have the map view auto refresh as soon the changes are made.

Software Requirements

1. ArcGIS Desktop 9.3.1 (Any license level)
2. ArcGIS .NET Assemblies (These can be installed separately from ArcGIS installation disk)
3. Microsoft .NET Framework 3.5 (It can be downloaded from Microsoft Website)

Installation

Download and run the Installer and you are ready to go.

Functionality

Layer Transparency is an ArcMap extension which adds a new toolbar to the ArcMap. The Layer Transparency toolbar has two buttons on it, one to open the Layer Transparency form and the other to display information about this tool.

Figure 1: Layer Transparency Toolbar

1. Show Transparency Layers: Click on the show transparency layers button to open the form listing the available Feature and Raster layers whose visibility, transparency, brightness and contrast can be changed.
   

   
   Figure 2: Layer Transparency Form
   

   The transparency form has three sections:

   a)    Appearance
   The appearance section provides three options to change the layer appearance settings:

   1. Transparency: The transparency can be changed for the Feature and Raster Layers
   2.  Brightness: The brightness can be changed for the Raster Layers only
   3. Contrast: The contrast can be changed for the Raster Layers onl

   b)    Layers
   The layers section provides the list of available layers for the selected appearance setting. Each layer shown has a check box on the left which can be used to turn on/off the visibility of the layer.

   c)    Controls
   There are five controls on the transparency form:

   1. Reset All: Resets the selected appearance setting to 0% for all the layers shown in Layers list and refreshes the map view
   2. Auto Refresh: Applies the changes live as they are made on the form
   3. Apply: Applies the pending changes and refreshes the map view
   4. OK: Applies the pending changes, refreshes the map view and then closes the form
   5. Cancel: Closes the form without applying any pending change

2.  About Transparency Layers: Click on the about transparency layers button to open the form displaying information about the tool release version and date along with the Spatial Vision company information.
   
   
   Figure 3: About Layer Transparency Form

Images of the Layer Transparency Tool in Action

Figure 4: The Countries feature layer is overlayed on top of Satellite raster layer with transparency of all the layers set to 0%

Figure 5: Changing the Countries feature layer transparency to 55% makes it appear very dim in comparison to the Satellite raster layer

Figure 6: A Satellite raster layer with Brightness set to 0%

Figure 7: The Satellite raster layer with Brightness set to 30%