This week’s blog will discuss how the mosaic dataset can help you put your bands together. A mosaic dataset can put these scenes together into one logical geodatabase entity.  Furthermore, it can mosaic all the scenes together as well.

A mosaic dataset can composite bands and also mosaic scenes.

There are two steps to creating a mosaic dataset:
1) Create an empty mosaic dataset
2) Add data to your mosaic dataset

Create a mosaic dataset
Create a new mosaic dataset, using the Create Mosaic Dataset tool.
The only compulsory fields are the Mosaic Dataset Name and Coordinate System.
Once you create the new mosaic dataset you need to add rasters into it.

Add Rasters to your mosaic dataset
Use the Add Rasters to Mosaic Dataset tool
- Choose the raster type that describes the sensor type for your data.
- Click the Browse button for the Input Data, and choose the parent folder of all your scenes.
- Run the tool
Your output should now contain all the raster scenes and all the bands in one mosaic dataset. You may need to refine your mosaic dataset, to be able to see all the images in your mosaic dataset with the proper rendering.

There are a two main ways to achieve the composite bands task:
- Composite Bands button on the Image Analysis window
- Composite Bands Geoprocessing tool

Image Analysis window
The Composite Bands button on the Image Analysis window allows you to merge all the layers with the click on a button. This composite is create immediately on-the-fly, since it is created as a virtual layer using the Composite Bands raster function.
1) In the Table of Contents, arrange the order of the bands, as you want them ordered in your output, where the top raster is band 1.
2) In the Image Analysis the layer list, select all the rasters that you want merged together.
3) Click on the Composite Bands button.  A new raster layer is created with all the rasters that were selected.

Composite bands Geoprocessing tool
The Composite Bands Geoprocessing tool will create a new raster dataset that is persisted on disk. Although this processing takes longer, you will have the output in a file format of your choice, which can easily be shared.
1) Open the Composite Bands geoprocessing tool.
2) Add the bands you want to combine into the input
3) Re-order the bands if necessary.  The top band will be band 1.
4) Choose an output path and file name for your output raster dataset.
5) Click OK to run the tool.

How do I put all the bands into one single dataset?
There are 2 main methods you can use to put your bands together. You can use Composite Bands (tool or function) or you can create a mosaic dataset.  If you want each scene to be independant of itself, then the composite bands tool is the best choice for you. If you prefer all your scene to be displayed in one dataset, then the mosaic dataset can composite all your bands, and also mosaic your scenes together.

Add many bands into one raster dataset by using Composite Bands.

Add all your bands from multiple scenes into one mosaic dataset.

Here is another great re-post from the Support Blog Site.  Click here for a link to the blog that lists many places you can go to get free raster data online.  Also make sure that you read the comments section, many of our users posted up more links for free data.

Thanks to Jeff S.

Additionally, we have more list of DEM data is publicly available.  Click here for a link to the PDF with elevation sources.

Thanks to Aileen Buckely.

So how do I delete my pyramids from my raster?
In order to remove your pyramids, you need to run the Build Pyramids geoprocessing tool with 0 levels built.
1) Open the Build Pyramids tool.
2) Choose the input raster dataset for which you would like to remove the pyramids

3) Click on the Environments button
4) Expand Raster Storage

5) For the Pyramid Levels parameter, type 0
6) Click OK on the Environment Setting
7) Click OK to run the Build Pyramids tool

Check the Properties of your raster dataset, and make sure that the pyramids have been removed.

With the update to the ArcGIS blogs as a result of creating a single blog that reflects ArcGIS as a system, you can now find more easily useful map-related information in posts from some of the other teams.

In this blog entry, we point out a number of posts that have been published on the Imagery blog that may be of interest to the Mapping Community. And conversely I note a number of Mapping blog posts that may be useful to the Imagery community. These blog posts will now appear if you search in either the Imagery or the Mapping category.

Imagery blog posts (starting with the latest post):

Imagery blog posts (starting with the latest post):

	Is your raster so bright you have to wear shades?	On March 27, 2012, By Simon Woo, Raster Product Engineer
	Clipping an image or raster in ArcGIS	On October 5, 2011, By Simon Woo, Raster Product Engineer
	Raster Enhancement: The Horizontal Legend	On April 27, 2011, By Simon Woo, Raster Product Engineer
	Create a custom color ramp	On April 20, 2011, By Simon Woo, Raster Product Engineer
	Advanced labeling for the stretch renderer	On April 13, 2011, By Simon Woo, Raster Product Engineer
	Can I create a customized colormap file in ArcGIS?	On November 2, 2010, By Simon Woo, Raster Product Engineer

Mapping blog posts (starting with the latest):

	An alternative to overlaying layer tints on hillshades	On March 8, 2012, By Rajinder Nagi, Cartographic Researcher
	Combining colored and grayshade rasters with high fidelity	On January 18, 2012, By Rajinder Nagi, Esri Cartographic Product Engineer
	Esri Color Ramps Version 3.0	On December 17, 2011, By Jaynya Richards, Research Cartographer
	Creating a grayscale version of any ArcGIS Online basemap	On November 19, 2011, By Rajinder Nagi, Esri Cartographic Product Engineer
	Symbolizing ETOPO1 data	On September 21, 2011, By Aileen Buckley, Mapping Center Lead
	Historical USGS topographic quads	On August 23, 2011, By Aileen Buckley, Mapping Center Lead
	Classifying Landsat image services to make a land cover map	On May 28, 2011, By Rajinder Nagi, Cartographic Product Engineer
	Using the Landsat image services to study land cover change over time	On May 13, 2011, By Rajinder Nagi, Esri Cartographic Product Engineer
	Landsat image services now available on ArcGIS Online	On May 10, 2011, By Natalie Feuerstein, Cartographic Product Engineer
	DEM resolution, output map pixel density, and largest appropriate map scale	On February 28, 2011, By Dr. A Jon Kimerling, Professor Emeritus, Oregon State University
	On map scale and raster resolution	On December 12, 2010, By Rajinder Nagi, Esri Cartographic Product Engineer
	Understanding curvature rasters	On October 27, 2010, By Aileen Buckley, Mapping Center Lead
	Using curvature rasters to enhance terrain representation	On October 27, 2010, By Aileen Buckley, Mapping Center Lead
	Symbolizing the bump map	On August 23, 2011, By Aileen Buckley, Mapping Center Lead
	Introducing the ArcGIS bump map tools	On January 21, 2010, By Rajinder Nagi, Esri Cartographic Product Engineer
	Mathematical relationships among map scale, raster data resolution, and map display resolution	On December 4, 2009, By Dr. A Jon Kimerling, Professor Emeritus, Oregon State University
	Symbolizing the hillshade for the World Topographic map	On November 24, 2009, By Charlie Frye, Esri Chief Cartographer
	Tips for hillshade data management	On March 11, 2009, By Charlie Frye, Esri Chief Cartographer
	Hillshades for analysis maps	On December 9, 2008, By Charlie Frye, Esri Chief Cartographer
	Hypsometric tinting	On May 9, 2008, By Aileen Buckley, Mapping Center Lead
	Choosing color ramps and displaying for hillshade rasters	On December 26, 2007, By Charlie Frye, Esri Chief Cartographer
	Setting the Z Factor parameter correctly	On June 12, 2007, By Charlie Frye, Esri Chief Cartographer

What do I do if my mosaic dataset pixel depth is not the same as all mosaic dataset items?
If you have a mosaic dataset that has mosaic dataset items with various pixel depths, you will want to use the Stretch raster function.  The Stretch function is used to virtually change the pixel range of your mosaic dataset item.

How do you use the Stretch function?
Let’s take an example where the mosaic dataset has a 16bit pixel depth, and the mosaic dataset item(s) in it are 8-bit.

1) Open the Footprint Attribute Table for the mosaic dataset. Right-click on the Footprint layer > then click Open Attribute Table.

2) Click on the Raster cell, of the item you want to change the stretch for. When you click on it, a small arrow will appear in the right side of that cell.

3) Click on the arrow, and it will open up the Properties for the mosaic dataset item.
4) Click on the Functions tab.
5) This shows you all the functions that take place on this mosaic dataset item. It looks like no functions have been performed on this item yet.
6) Right-click on the top function, point to Insert, and then click Stretch Function. RasterInfo is not really a function, but something has to be there as a place holder.

7) Adjust the Statistics of the Output Minimum and Output Maximum. There is no perfect way to set this, but you can look at the minimum and maximum of your mosaic dataset first. Then you can adjust the values accordingly.

8 ) Click OK to save the new statistics.
9) Click Apply to apply the new function changes.

If your mosaic dataset item is still not displaying with a decent contrast, try to follow steps 7 through 9, while adjusting the minimum and maximum output. In my particular example I needed to use 0 and 1300 in order for my mosaic dataset item to display fairly well.

Before we jump into this week’s blog, I wanted to mention that our Support Staff have their own Support Services Blog series.  Their blogs cover a wide array of topics that many of you may have called them about.  This includes some raster and imagery issues.  If you haven’t seen their blogs before, it is another great resource to find information that may help you out.

Today’s Imagery Blog is a re-post to a great Support Blog that was written by Jeff S.: Is your raster so bright you have to wear shades?

Summary: Sometimes your raster dataset appears to look different than you have seen it before.  Or you look at the image and think that it is way too bright. If this is something that you have encountered before, then you will probably want to read more about this issue.

Reposted from the Support Center Blog
Original post written by: Jeff S.

This year’s Esri Developer Summit will take place from March 26^th to March 29^th at the Palm Springs Convention Center.
        More information about the 2011 Developer Summitt
        View the Agenda

Come by and meet the members of the Raster Team, whether you have a question, or just want to meet some of the team. There are several way to meet us: you can come by the Showcase Area, you can attend our Technical Workshops or Demo Theaters, or you can join us at the Meet the Team event. 

Esri Showcase

The Raster team will be located at the Desktop Island and also at the Server Island. 
The Esri Showcase has the following hours:
Monday            11:00 am – 7:30 pm
Tuesday            12:30 pm – 6:00 pm
Wednesday      10:00 am – 6:00 pm

Technical Workshops

Creating Mosaic Datasets and Publishing Image Services Using Python
Tuesday, March 27^th @ 4:30 pm
Mojave Learning Center (Renaissance Hotel)

Programming Image Services Using ArcGIS API for Microsoft Silverlight
Wednesday, March 28^th @ 4:30 pm
Smoketree A – E

Demo Theaters

Working with Raster Data Using Python
Monday, March 26^th @ 3:45 pm
Demo Theater 2 – Oasis 1

Extending Mosaic Datasets in C#
Wednesday, March 28^th @ 1:00 pm
Demo Theater 1 – Oasis 1

Meet the Teams

Tuesday March 27^th 5:45 pm – 8:00 pm
by the pool

Why does my mosaic dataset and the items have different pixel depths?
When you create a mosaic dataset, you can choose what the pixel depth of the mosaic dataset will be.  If you do not choose the pixel depth (you leave that option blank), then the first item added to the mosaic dataset will set the pixel depth. However you are able to add a raster of any pixel depth to your mosaic dataset.  Therefore you may have a mix of pixel depths within your mosaic dataset.

Will my mosaic dataset still display?
Your mosaic dataset will still display, however some of the items that do not have the same pixel depth as the mosaic dataset may display very dark or very light. When your mosaic dataset has a higher pixel depth than your item(s), then the item(s) will display very dark in color. When your mosaic dataset pixel depth is lower than your item(s), then your item(s) will display very light in color.

Mosaic dataset pixel depth is higher than the pixel depth of the item.

Mosaic dataset pixel depth is lower than the pixel depth of the item.

It is always good practice to make mosaic datasets that have items of similar properties. If you do mix pixel depths within your mosaic dataset, you may have to use the Stretch function in order to display all the items with better contrast.