A Tale of Two Pixels: Nodata and Transparency in GeoExpress

GeoExpress is a software package that provides image compression technology for converting raw imagery into the compressed MrSID format. Not all MrSID files are created equally, however, which makes understanding the differences between them very important. MrSID Generation 3 (MG3) files are a legacy format still used by many GIS applications. MrSID Generation 4 (MG4) […]

MrSID Compressed

Why are Pixels Missing in my Image?

When I convert raw data to a MrSID file there are many areas within the image that are the wrong color. Here is the raw image: And here is the compressed MrSID: Some explanation of how GeoExpress and ArcMap handle nodata is in order. To learn more about missing pixels in your MrSID image, visit […]

Despeckling in MrSID Compressed Images

Speckling artifacts happen because compressing images to MrSID at high compression ratios requires approximating colors. In other words, “black” becomes “almost black.” While the human eye doesn’t ordinarily notice the difference, this can make it difficult (not to mention ugly) to mosaic images together. Speckling also happens with other background colors depending on the nodata […]

MrSID Compression and Despeckling


National Security Depends on Useful Information in the Hands of Diverse End Users

The term ‘National Defense’ conjures up notions of an army, navy and air force ready to protect the homeland from organized military or loosely affiliated rebel aggressors. In today’s complex world, however, this term has widely been replaced with the blanket title of ‘National Security’ due to the many activities that national governments now undertake […]

Express Server 9.0.7 Now Available

LizardTech issued a patch for Express Server this week, the fast and simple image-delivery server for MrSID. Express Server 9.0.7 is now available! This patch release addresses two main things: 1. Users can now install to the website of their choice (not just the default website) 2. Fixed a bug that was causing a server […]


drone aerial

As UAS Technology Evolves, MrSID Playing a Key Role

In case you’ve somehow missed the news, the mapping business is undergoing one of its biggest disruptions since Landsat thanks to the proliferation of those little unmanned airplanes and helicopters that are probably flying over your house right now. Depending on who you ask, there are literally hundreds of legitimate commercial companies building and selling […]