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Map

Creating raster datasets from source images – best practices

A Map Series

This is a technical article that shows you step by step how to create a raster dataset in SDE from multiple georeferenced image files.  Todd Zagurski from Regional Planning and Mark Greninger from the CIO’s office created this document.

Problem: You have a map series that has been scanned and georeferenced, but exists as many individual images which makes access cumbersome.

Solution: Use these instructions to create a single seamless raster dataset.

Additional Benefit: By creating a single seamless image, you will able to see any errors in your referencing at a glance – holes show up extremely quickly.

History

LA County’s Regional Planning Department had scanned 3 historic map series (House Numbering Maps, Index Maps, and Township, Range Section Maps).  Each series of maps included between 50 and 100 maps that were part of a map grid (see an example snapshot to the right).

The goal was to create a single, seamless raster dataset in our Enterprise GIS database that would enable Regional Planning to view the entire series as a single image.  There were a number of issues, including the fact that each scanned image had a slightly different pixel size (meaning the sderaster mosaic command wouldn’t work).  As well, most of the images were single-band (gray scale), but a couple were color, causing issues too.

A fair amount of effort was expended getting the data right, but now it’s a single seamless raster dataset available through a single dataset.

Instructions:

The documents below include detailed instructions on how to flatten your data, create a raster dataset, and load the data into your database using the Workspace to Raster Dataset command.

 

 

WS 2 Raster

 

Raster Dataset (seamed)

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