Latest Contributions by PeterBecker

Are you sure the issue with MrSID is not related to the SOC not having access to data stored on a SAN? Do other formats of imagery stored on the same storage system display? Concerning reading ECW files on a Server. The issue is not a technical one, but related to licensing. ECW is a proprietary format that can only be read using libraries provided by ERDAS. The libraries to read ECW are restricted by ERDAS and may not be used on server machines, so the libraries are not included with ArcGIS Server distribution. To enable the reading  of ECW files on a server machine, ERDAS have recently created �??ECW for ArcGIS Server�?� that can be purchased from ERDAS and provides a licensing mechanism. More information on this can be found at http://www.erdas.com/products/ERDASExtensionsforArcGIS/ECW_for_ArcGIS_Server/Details.aspx The alternative to for serving is to convert the ECW files into a more open format such as BIG TIF, which can handle very large size and includes a range of different compression formats. For RGB compressed imagery I would recommend Tiled JPEG compression. For the same visual quality the file size of the JPEG compressed TIF files will be about 1.5x larger. JPEG though is very quick to decompress reducing the CPU load on the  server. ... View more

The mosaic dataset acts as a form of catalog that defines the location of all raster data sources as well as associated metadata and information on how the data should be processed as it is accessed. When a Mosaic Dataset is added directly into ArcGIS Desktop, ArcGIS Desktop accesses the required imagery directly. If the data is in a file system then the required files are opened and read, if the pixel data is stored in an enterprise database then a connection is made to the database and the pixels read from the database. If the mosaic dataset is served as an image service through ArcGIS Server then when a client application makes requests for imagery it is ArcGIS Server (one of the SOCs) that makes the required requests for pixels data from the file system (or database connections) prior to performing and required processing before streaming the pixels to the client application. ... View more

Gray image are displayed if the server can not access the required images to generate the view. The scale at which this changes is most probably the scale where overviews are displayed. Most common is that the overviews are stored local to the server and can be accessed by the server, but the original images are stored on a SAN/NAS and may not be accessible by the server. Check that the users ArcGISSOC has read access to the original data. This is the user under which the Server tries to access the data. You see the images when directly using the MosaicDataset since you as a user have access. ... View more

In 10 or 10 SP1, when no mosaic method is specified, then the server will use 'None' as the MosaicMethod. ZOrder won�??t work when �??None�?� is used. ArcMap knows the default of the service and always specify that default method. This was fixed in SP2 such that the default MosaicMethod will be used by default. The solution for this issue is: 1. set mosaic method explicitly in REST (using web API), or 2. install SP2 (recommended) ... View more

Assuming the imagery is georeferenced then the best would be to create a Mosaic Dataset of the imagery. This can easily be done by creating using the Raster Datasets, Raster Type and defining the required directory as the Workspace to add. For such an application there is no need to create overviews of the mosaic dataset, but it is advantageous to create pyramids on each image. Publish the mosaic dataset as an image service. You will then want to create your application such that it access the imagery using LockRaster to specify the specific (or set) of images to be displayed. For samples of Silverlight code to do this review the "Image Service Explorer Sample" in the resource center. ... View more

ZOrder can be used to force the order of the imagery. The lower the number the higher the priority. Images with ZOrder < 0 will be always be displayed top most. Then the images with ZOrder =0 will be displayed according to the Mosaic Methods. Then the images with a ZOrder>0. You could force the ZOrder, but then other mosaic methods will not work. Generally  I would suggest including the mosaic method into the REST request. ... View more

The issue is most likely related to the Mosaic Method. With REST you need to explicitly define the mosaic method to be used, else it will default to None, which results in the first file being show on top. ... View more

It depends on the type of Web client you are using. If using the REST API then the web application can define a Colormap function to be applied on the server. see Raster Functions under   http://help.arcgis.com/en/arcgisserver/10.0/apis/rest/index.html Some web applications based on Flex or Silverlight can apply color maps on images from image services. If using a more simplistic / generic web app then you will need to apply the color map on the server. If serving a single image the simplest method is to define the renderer in ArcMap then save it as a Layer (LYR) and publish this Layer as an image service. If serving a large collection of such imagery create a Mosaic Dataset of them first. There are then two ways to apply the color map. Either as a property of each raster or as a property of the mosaic dataset. If the data is categorical or the color map is to change from image to image it is better to define the color map for each Raster. (See Batch Edit Raster Functions to apply to multiple rasters). If the 1 band images can first be mosaicked and then a the color map applied, it is easier to add the color map function as a property of the mosaic dataset. When using such color maps you should also consider what sampling method and compression to be used to access the data. If using categorical data then set the sampling to nearest and use PNG or LZW compression to access. If the data represents continuous image then use bilinear and JPEG compression for access. ... View more

I presume you are using Image Service Definitions in 9.3.1 It seems you are doing the link the wrong way. You need to join the Image Service Definition footprints to the new footprint geometry. IE right click on the Image Service Defintion footprint and then join this footprint to the new geometry feature class (shape file). The tool uses selection sets so ensure that the records that you want to be replaced are selected (else none so that all records are processed). Check that the link between the ISDef footprints and the shape file containing the new footprints is correctly linked. Preferably have some other attribute in the new shape file and check that these are displayed as part of the footprint attribute table prior to running the tool. ... View more

If you have large images (>5000 columns) then it is advantagous to have images with pyramids created. For small images there is little or no advantage. The pyramids (such as .OVR file, .RRD; internal overviews in TIF files or MrSID etc) are used by ArcGIS (and in Mosaic Datasets) to access imagery at smaller scales. Consider the case of a large image with say 20,000 columns. If pyramids are created they would have multiple levels with 10000, 5000, 2500, 1250, 625 columns. These multiple levels of pyramids would be used making access faster at the smaller scales. The screen area covered by the pyramids gets smaller and smaller though and a point is reached when covering the screen would require opening too many files. By default when rasters are added the LoPS value is set based on the level at which the Num Cols goes <1500. In the above cased 2500. When generating overivews these would then get created at a scales equivalent to about 2x this scale. The result of this is that the overview are created at scales when the number of colums in the pyramids woudl go < about 1500 (or when too many images would generally be needed). The use of pyramids therefore increases the scale at which overviews are created. For overlapping imagery this has the advantage of increasing the scales at which the mosaic methods work and reducing the number of overviews. For applications where there are only sets of tiled images, or if the images are small then there is no advantage of having pyramids. ... View more

When you add the ISDef turn the compute cell sizes off. Alternative is to in the ISDef create two new fields (say Min_PS,Max_PS) and use calculate to set them to the same value as the original. Then Import the ISDef. Then reset the MinPS and MaxPS by doing calculate using Min_PS and Max_PS. Note that there was a change between ISDef and MosaicDatasets in that in an ISDef the MinPS,MaxPS values are always in meters, while in a MosaicDataset the value is in the same unit as the SRS of the mosaic dataset. If you create the MD in ft then use [MinPS]=[Min_PS]/0.3048. If in Decimal Degrees use [MinPS]=[Min_PS]/111111. ... View more

The serving of a Mosaic Dataset requires a Licence for the Image Extension to ArcGIS Server. It seems you have registered the Image Server (9.3 technology that can be installed and run at V10, but uses ISDef files), but not ImageExtension (core to ArcGIS Server that does not require a separate install, but does require licensing). ... View more

In sort No. The optimized serving of single images ( E.G.a large .img file) as image services only requires ArcGIS server. When served as an image service the image is quickly accessible as a web service directly in ArcGIS applications, but also via SOAP, REST & KML Image Service include a number additional functionality. For example the the client application can define the compression for transmission enabling faster access even over low band width networks. At V10 image services also work on Raster LYRs that include processing and the client application can define processes to be applied. For example a single elevation raster can be served as elevation, hillshade, slope and aspect. Alternatively to using image services the image can be included in an MXD document and then cached. These map cache tiles can then also be served as a static background with near negligible load on the server. Map cache provides the highest scalability and recommended if you have a static base image that you wish to server to large numbers of web applications. The ArcGIS Server Image Extension is recommended when serving large collections of imagery, whether these are many tiles of orthoimagery possibly in different formats and projections, or lower level imagery from satellites or aerial sensors. As a bit of background: Image Server is a technology in which the server performs dynamic mosaicking and on-the-fly processing of imagery. It used to exist as a separate stand alone server product at v9.2. At v9.3 image services were added as a core capability of ArcGIS Server to enable the optimized serving of imagery over the web. Using image services any image or raster could be served as an image service. A single image could be server as an image service. The ArcGIS Server Image Extension extended ArcGIS server and provided the capability to serve large collections of images defined in an Image Service Definition (ISDef). ArcGIS Server passed requests that required dynamic mosaicking and on-the-fly processing to the separate image server. At V10 the image server technology was fully integrated into ArcGIS (both desktop and server) and the ISDefs were replaced by Mosaic Datasets stored in the geodatabase. The Mosaic Datasets are the optimum data model for image data management. They define a catalog of images, associate metadata and parameters for transforming the imagery into different image products. They can be created using ArcGIS Desktop (Editor or Info) and used directly by any ArcGIS application with the required processing being performed by the client application. The ArcGIS Server Image Extension is required to server Mosaic Datasets as image services. When served as image services, Mosaic Datasets are accessible as large virtual image with all required processing applied on-the-fly by ArcGIS server. They are also accessible as catalogs that enable search and discover of imagery. ... View more

I can not reproduce. How are you creating your subset? I used the clip and did a subtract on the original and the clip and got 0 back. ... View more

Yes the technology uses any existing pyramids. The system does not necessarily use all the levels though. When a rasters is added the system computes the LoPS and HiPS values for the rasters. The LoPS is based on the high res imagery, the HiPS is based on the availability of pyramids and their size. Generally the HiPS is set to the size of pixel in the pyramid where the NCols>1500. What this attempts to do is ensure that the larger pyramids are used by not the very small ones. At the larger scales is it better to create overviews that are a mosaic of multiple images so that the system does not need to open a large number of files at smaller scales. All these value can be manually changed by using the Calculate tools. V10 is better then V9.3 in that the overviews are automatically used if they exists. In V9.3 when ingesting the imagery the system looked to see if the overviews exist and if they were added later it would not recognize them. ... View more