Tag Archives: aerial photography

Publishing ECW Imagery with ArcGIS for Server

Being in Australia one of our most popular image formats is ECW. In other countries ECW is not as prevalent. This is geographic anomaly as the ECW format came from ER Mapper, developed out of Perth. ER Mapper was a cost effect Image processing product which provided very good image processing capabilities at a good price point. This led to wide market penetration in Australia but not other parts of the world. One of the by products of this legacy is the ECW image format. Based on the wavelet compression technology it provides for very good image compression and provides good speed to display. Hence it’s wide use here in Australia..

In other parts of the world the same compression is achieved using either the MrSID format or JPEG 2000. Both are wavelet compression technologies and both also provide good speed to display. The fundamental difference between all three formats is that MrSID and ECW are licensed formats while JPEG 2000 is an open format.

What does this mean to ArcGIS users?

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Geotiff issue in version 10

If you are having issues with GeoTIFF images that were viewable in ArcGIS 9.3.1 but not visible in ArcGIS 10 read on!

  1. Click Customize on the Main menu and click ArcMap Options (or ArcCatalog Options, depending on the application you are using).
  2. Click the Raster tab in the Options window.
  3. Within the Raster tab, click Raster Dataset and check the Use world file to define the coordinates of the raster check box.
  4. Click OK.

The Tif images are now viewable in ArcGIS Desktop 10! See this help item for more information.

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Time-Enabled Rasters

Visualizing change over time is an effective way to analyze local or global trends and predict future scenarios.

In GIS, much information of this type—for example, sea-surface temperature, annual births, labour market statistics, vegetation type, land-use data—is commonly stored in raster format, and it’s very useful to see these data animated. So how do you make your rasters time-aware? An easy way to is to take advantage of two new features available in Version 10: time-enabled layers and the mosaic dataset.

Follow these steps to create an animation showing change in sea surface temperature over time, or vegetation change in South-West QLD. There’s a tonne of data to show change over time—and now we have an easy way to visualize it in ArcGIS!

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Multiple year orthophoto’s in a mosaic dataset

Your organization may have a collection of aerial photography from three years, such as 1995, 2005, and 2008 and you want to publish these as a web service. These may have different resolutions, such as 1 meter, 2 feet, and 0.5 feet. The earliest collection could be a panchromatic in a Geographic projection and the other two are color in a UTM projection.

The best way to manage this data is as separate source Mosaic Datasets and Derived Mosaic Datasets in a Geodatabase. Using source and derived Mosaic Datasets generally makes the management easier while maintaining best performance.

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