Tag Archives: G-FAQ

The RapidEye Constellation – A Data Continuity Plan is in the Works

Posted on February 7 2013 by Katie

RapidEye, a leader in medium-resolution, wide-area, repetitive coverage of the Earth through its constellation of five satellites announced a positive update on the health and lifespan of its satellites. In addition, Michael Oxfort has been appointed to lead the development of the company’s data continuity strategy.

“The RapidEye System has proven to be extremely robust,” commented Brian D’Souza, PhD, RapidEye’s Head of Engineering. “In August of 2008, we experienced a nearly flawless launch. After four years in orbit, the constellation continues to operate effectively, with all five satellites fully operational. Based on the current performance of the satellites and the … Read more

Free For All – 7-Zip

Posted on January 10 2013 by Katie

Data storage is not free as we all know, and many geospatial files are really large, especially high resolution aerial and satellite imagery. In fact, the minimum size order of 50-cm color WorldView-2 satellite imagery with 16-bit depth has a file size over 500 megabytes (mb)! So then, what is a viable solution for long-term storage?

I am guessing that many of you use the same solution as I do – file compression. If that is the case, you need to give 7-Zip a look. It is a freeware program that does a superb job at compression with a lot … Read more

G-FAQ – What is the Best Compression Format for TIFFs?

Posted on January 10 2013 by Katie

For this month’s Geospatial Frequently Asked Question (G-FAQ), I explore a topic that perhaps some of us have given little consideration to: file compression. Specifically, I look at file compression of TIFFs which are commonly large datasets that we have to store for both short and long time periods. Take for instance the minimum order of 25 square kilometers (sq km) of 50-centimeter (cm) WorldView-2 imagery with 8-bit depth, this dataset alone is 400 megabytes (mb). Now consider the enormity of a 1-foot aerial collection over an entire county, and surely the topic of file compression now makes a bit … Read more

G-FAQ – What is the Importance of Geographic Transformations in ArcGIS?

Posted on November 20 2012 by Admin

For this month’s Geospatial Frequently Asked Question (G-FAQ), I turn my attention to the topic of projections in ArcGIS with a focus on geographic transformations. Geographic transformations are those options that appear at the bottom of the Project Toolbox interface for both features and rasters. While the transformation will auto-populate (in Arc 10.1 at least), there is reason to be mindful of the option that is chosen.

With this in mind, the November and December G-FAQ’s will address this core set of questions:

What exactly is a geographic transformation? How do the various Projections and Transformations toolbox functions differ? What … Read more

G-FAQ – How do I Open and Color Balance RapidEye Imagery in Photoshop?

Posted on October 17 2012 by Admin

For this month’s Geospatial Frequently Asked Question (G-FAQ), I shift gears slightly from my normal approach with a primer on using a data in a commonly used software application. We have seen an increased interest in using 5-meter natural color RapidEye imagery as a back drop in movies, ads and apps for large-area coverage; however working with this data in Photoshop, a very common graphic design software package, is not as straight forward as it may seem. And when you need to get your project done yesterday, even a five minute delay is too long to wait!

As such, this … Read more

G-FAQ – Why is Bit Depth Important? Part 2

Posted on September 18 2012 by Admin

For this month’s Geospatial Frequently Asked Question (G-FAQ), I continue the discussion started last month on bit depth and its impact on satellite imagery. In the first part of the series, I addressed the basics of the topic, including a discussion of binary versus base-10 numeric systems as well as the bit depth ordering options available for satellite imagery. In this second part, I focus on the operational side of bit depth by providing advice on how to work with 16-bit imagery in ArcGIS as well as an explanation of when to order 8-bit versus 16-bit satellite imagery.

As … Read more

G-FAQ – Why is Bit Depth Important?

Posted on August 28 2012 by Admin

For this month’s Geospatial Frequently Asked Question (G-FAQ), I pivot to a topic that deserves more attention than it gets, and that is bit depth. Some of you may have heard this term when ordering imagery from Apollo Mapping or perhaps when downloading free Landsat data without understanding its implications. As such, let’s delve into this topic, addressing the following set of questions:

What exactly is bit depth and why is it important when ordering satellite imagery? Is 16-bit imagery harder to work with? When should I order 16-bit imagery versus 8-bit depth?

To start of this discussion, it is … Read more

G-FAQ – Why Can I See Some Small Objects in Imagery and Others Not?

Posted on July 19 2012 by Admin

For this month’s Geospatial Frequently Asked Question (G-FAQ), I explore the topic of spatial resolution as it relates to satellite and aerial imagery; and its impact on the objects that you can and cannot see in this data. Have you ever purchased or downloaded imagery with 1-foot pixels expecting to see a feature that was approximately two feet in diameter, for instance a small bush, only to be disappointed when you could not find the feature when you inspected the full resolution data? If you answered yes in your head just now, then this GFAQ is the article for you … Read more