Category: Imagery

Oh where oh where have my pyramid files gone?

For those of you working with raster pyramids, are you asking yourself:
    “Where are my pyramid (RRD) files?”
    “And what are these OVR files that are being created?”

Where are my pyramids?
When you create or rebuild pyramids in ArcGIS 10, RRD files are no longer created.  Your new pyramid files are now named with an OVR extension.

Is that the end of RRD files?
No. Existing RRD files that are not altered, will stay as RRD files.
As well, any pyramids created for the IMG format will still be created as RRD files.

Why do we need an OVR file?
The RRD file still serves its purpose as a pyramid file.  
The OVR file has the capability to compress pyramids during creation. The OVR file can be compressed with JPEG or LZ77 compression. This mean smaller pyramid files!  This can especially be seen when JPEG compression is applied.

Why wouldn’t I always choose JPEG compression then?
Not all data can be compressed with JPEG compression. Whenever JPEG compression cannot be used, JPEG pyramids cannot be created.  On the other hand, LZ77 compression can be used for any data type.

 

Contributed by: Simon Woo

Posted in Imagery | Tagged , , , | 2 Comments

Raster Functions

What are Raster Functions?
ArcGIS 10 allows processing to be applied to rasters. This processing is applied on-the-fly so as not to change the original data. The mechanism by which this processing is applied to rasters is called raster functions.

Raster functions are operations performed on one or more raster datasets. They can be used to apply on-the-fly processing to individual rasters, rasters which make up a mosaic dataset, or a mosaic dataset. A raster function has parameters that can be edited by the user to control the processing it performs. These parameters can be edited using the Raster Function Editor page, which can be found at various places in ArcGIS Desktop.

Raster functions can be chained together to apply more complex processing to a raster. The chain works in such a way that the output of one raster function becomes the input to the raster function applied on top of it in the chain, similar to process chains used in the ArcGIS Image Server software.

Raster Functions can also be applied through the ArcObjects framework by using the various SDK’s. The SDK for raster functions also supports customization, so users can write their own functions that implement the processing they desire.

How to apply Raster Functions?
Raster functions can be applied to rasters in Desktop using the Image Analysis window. This window allows the user to apply different kinds of processing to one or more rasters.

The Functions tab in the Mosaic Dataset Properties page is used to apply processing on top of a mosaic dataset.

 
To apply processing to the rasters that comprise a mosaic dataset, there are two methods:
1.    The Functions tab in the Raster Viewer can be used to apply or edit the processing on a single raster in a mosaic dataset.

2.    The batch function editor can be used to insert or remove functions from multiple rasters in a mosaic dataset.

 

Contributed by: Prashant Mukesh Mangtani

Posted in Imagery | Tagged , , , | 2 Comments

Image Classification toolbar introduced at ArcGIS 10

A new toolbar, Image Classification, has been introduced at ArcGIS 10 to make image classification tasks both faster and easier (to use this toolbar, you need the Spatial Analyst extension).  Expressed simply, the image classification process converts multiband raster imagery into a single-band raster with a number of classes, which you can then use to make thematic maps or for further analysis. Example applications for image classification include landcover mapping and landuse change detection. Continue reading

Posted in Analysis & Geoprocessing, Imagery | Tagged , , , , , | 1 Comment

FREE Live Training Seminar – Visualizing and Analyzing Imagery with ArcGIS 10

Title: Visualizing and Analyzing Imagery with ArcGIS 10

UPDATE: Now available as a recording.

————————————————————————————————————————

When: Thursday, August 12, 2010
              9:00 a.m., 11:00 a.m., & 3:00 p.m. Pacific Time (US & Canada)
              12:00 p.m., 2:00 p.m., & 6:00 p.m. Eastern Time (US & Canada)
              4:00 p.m., 6:00 p.m., & 10:00 p.m. UTC/GMT 

Where: Online

Cost: FREE

 

Contributed by: Simon Woo

 

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Raster Types – Part Two

As you now know about raster types in mosaic datasets, let me now go a little deeper into
the different types of raster types and they how can they be modified for your
specifications. There are 22 predefined
raster types. Each has their respective templates to choose from while adding
data.

·
Raster
Dataset Type
: – The Raster
Dataset raster type refers to any raster format supported by ArcGIS which
include Tiffs, Jpeg, JP200, MrSID, IMG, etc. This type can also be used to add
another (existing) Mosaic Dataset or a Raster catalog to the newly created
Mosaic Dataset.

·
Sensor
products
:- There are many sensor products to choose
from such Quick Bird, Landsat, Geo Eye, World View, Geo Eye, Ikonos, SPOT and
each has properties that can be refined to modify the functions and band
combination applied to the imagery when it’s added

·
Image Service
Definition
: – The image service
definition raster type allows you to add image service definitions (*.ISDef)
files created with ArcGIS Image Server. You can add these files by pointing to
either a particular file or a workspace or folder location containing many
.ISDef files.

·
Image Service
Reference
:-The image service
reference raster type allows you to add image service reference (*.ISRef) files
created from image services (typically served from ArcGIS Image Server). You
can add these files by pointing to either a particular file or a workspace or
folder location containing many .ISRef
files.

·
Raster
process Definition
: – The raster
process definition raster type allows you to add raster process definition
(*.RPDef) files. You can add these files by pointing to either a particular
file or a workspace or folder location containing many .RPDef files.

·
Web services: – You can add several types of Web services as
source data to a mosaic dataset. These include cached map services and image
services from ArcGIS Server; WMS services; and other cached Web services, such
as Bing Maps and services from ArcGIS Online.

·
Frame
camera/Aerial triangulation
: -
Imagery related to remote sensing aerial triangulation using aerial
triangulation and digital and analog frame cameras such as ISAT, MatchAT,
Applanix are also supported.

·
Tables: – Using the tables raster type, you can add raster
catalog, Mosaic datasets, dbf file, ISDef , tables with path to your mosaic
dataset.

·
Military Data: – Military data such as CADRG , CIB, DTED, ECRG are
supported . features of this data include Metadata such as Production dates ,
Latitude longitude information ,Match/Merge versions and well as Security
Classification.

For each raster type there are properties that you can modify before adding your
raster data to a mosaic dataset. These include choosing a product type,
specifying a particular band combination and a stretch, identifying the DEM for
orthorectification, and modifying the parameters for pan sharpening. The
properties that are available depend on what is supported by a particular
raster type. Raster types are stored with .art extensions. Any time you make an
edit to the raster type, you can save it to a new .art file so you can load
additional data at another time using the same modifications.

 

Contributed by: Sangeet Aloysius Mathew

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Raster Types for the Mosaic Dataset

Raster data is added to a Mosaic dataset by specifying a raster type. The raster type identifies metadata, such as georeferencing, acquisition date, and sensor type, along with a raster format.

The method of adding data is specific to the raster type selected during the Add Rasters To Mosaic Dataset process. Once the raster type is selected, you have the option to choose between various templates where you might want to define a specific band combination or add a filter when the data is added rather than later. You can modify any raster type by changing its default properties, such as the band combination, or defining the elevation model to use when orthorectifying data.


Each Raster type template comes with a predefined set of functions in the function chain. However you can add or modify the function chains to do specific processing on the imagery. Function chains applied on the whole mosaic dataset will affect every raster within the mosaic dataset.

There are various raster types that can be specified to load data such as sensor data, elevation data, and satellite imagery into a Mosaic dataset. Stay tuned, a blog describing the various raster types will be coming soon.

Contributed by: Sangeet Aloysius Mathew

Posted in Imagery | Tagged , , , | 5 Comments

Imagery support at the User Conference

While you are down in San Diego at the ERSI User Conference, be sure to stop the Raster Booth (Geodatabase Island) or the Imagery Island for all your raster and imagery questionscomments.

Here is a map of the ESRI Islands in the main Exhibit Hall (the ESRI booths are towards the back of the Exhibit Hall).

This picture is zoomed in into the Raster and Imagery sections.

Lastly here is an picture of what the raster booth looks like.

Contributed by: Simon Woo and Jie Zhang

Posted in Imagery | Tagged , | 1 Comment

Increase the value of your imagery investment – Create a mosaic dataset

Managing and disseminating imagery is a big deal. They not only furnish bulk of useful information but are tough to handle without efficient tools. To address our exponentially growing appetite for imagery, mosaic datasets are out here to help us optimally manage and use loads of data easily.

Creating a new mosaic dataset is pretty straight forward, and can be done using the new Catalog Window in ArcMap. The first step will be to create or find a target geodatabase.  Then, create a new mosaic dataset within the geodatabase, using the New > Mosaic Dataset context menu.

This brings up the Create Mosaic Dataset tool, which only requires two pieces of information to run:
    – the name of the mosaic dataset
    – and the coordinate system definition for the new mosaic dataset. 
Executing this tool results in an empty mosaic dataset within your geodatabase.

An empty mosaic dataset will be added to the table of contents as a special group layer: ‘Boundary’, ‘Footprint’ and ‘Image’. ‘Footprint’ shows extents of rasters within the mosaic dataset, while ‘Boundary’ defines the extent of the whole mosaic dataset, and ‘Image’ houses and controls the display of the actual raster data.

Once you have created the mosaic dataset, you can add single or multiple raster datasets to the mosaic dataset using the Add Rasters to Mosaic Dataset tool. (Add Rasters menu item while right-clicking on the mosaic dataset).
This tool requires the ‘Raster Type’ and ‘Input’. Raster Type serves as a protocol for extracting all the relevant details a particular type of raster (the file format, kind of product, and metadata to include in the mosaic dataset’s attribute table). However, in case of ambiguity or lack of information the generic raster type, ‘Raster Dataset’ can be used to add any raster file format supported by ArcGIS.

 

The drop-down menu for ‘Input’ allows you to choose the file-sources for the input datasets:
    – ‘workspace’  – indicates a folder to consume all raster datasets within it
    – ‘file’ – adds single datasets based on file extensions
    – ‘dataset’ – adds data from raster datasets, mosaic datasets, raster catalogs, or tables
Optionally, you can choose to check ‘Update Overviews’ to generate overviews, which are reduced-resolution images created to increase the display speed.

When creating a mosaic dataset from within ArcMap in the Catalog Window, the new mosaic dataset will be readily available for you in the table of contents. You can begin using it directly in ArcMap. Or you can even serve the mosaic dataset as an image service from the Catalog Window. Storing, managing, and disseminating imagery is made easy, ain’t it?

More to come about working with mosaic datasets in future blog posts!

 

Contributed by: Sirisha Karamchedu

Posted in Imagery | Tagged , , , | 3 Comments

Imagery News Flash: New resource center, new video, and raster processing specialists at the UC

New Imagery Resource Center

The new Imagery Resource Center is now available. The new resource center has been updated for the latest release of ArcGIS, and includes great enhancements to the overall user experience. While you are at the Imagery Resouce Center, you can even access our Imagery Blog archives.

  

New video online: Creating a mosaic dataset with sensor data

There are several videos available online at the Imagery Resource Center.

A brand new video has just been placed online. The video outlines how to create a mosaic dataset using sensor data.

   

Raster Processing Specialists @ the UC

At the ESRI User Conference, there will be a specified time set aside where you can meet specialist to help answer your questions. There will be Raster Processing Specialists available at the Geodatabase Island (in the Showcase area) on Thursday July 15th between 11:00AM till 1:00PM. Click here for more information about the specialist at the Geodatabase Island.

 

Contributed by: Simon Woo

 

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New supported Raster Formats at ArcGIS 10.0

ArcGIS 10 supports several new raster formats for easier transitioning of data between ArcGIS and third-party software. The short list below is a subset of newly supported formats and includes some of the more commonly used formats.

New read-only formats include:

  • BAG (Bathymetry Attributed Grid): Elevation data which usually has two or three bands (elevation, uncertainty, nominal elevation).
  • FAST: A file sometimes associated with Landsat 7 and other sensor platforms. Products include the *name*_HPN.FST (panchromatic band), *name*_HRF.FST (6 band multi-band), and *name*_HTM.FST (2 thermal bands).
  • GFF (GSAT File format): Complex data
  • ISIS (2 &3): USGS Astrogeology data
  • JAXA: PALSAR products levels 1.1 and 1.5
  • RS2: Radarsat 2 complex data
  • TIL: Digital Globe / Earth Watch header file for individual and tiled imagery

New read and write formats include:

  • Big TIFF: Tiff images larger than 4 GB in size. Writeable through GP, data export, or code.
  • TIFF with JPG compression: Writeable through GP, data export, or code.

New writeable formats include:

  • FLT: Floating point raster format (write through code only)
  • DTED: Elevation data writable through the new “Raster to DTED” GP tool or through code.

We hope you enjoy these new capabilities. For a complete list of all supported raster formats including read and write information visit the supported formats help documentation.

Happy Formatting!  

Contributed by: Robert Berger

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