Gaining from High-Resolution Imagery

Marathon Oil Corporation

Headquartered in Houston, Texas, Marathon is the fourth largest U.S-based integrated oil and gas company and the fifth largest U.S. refiner with a refining capacity of 974,000 barrels per day. In 2006 the company took in $65 billion in revenues and netted $5 billion in income. Marathon is a petroleum refiner, marketer and transporter operating primarily in the Midwest, Upper Great Lakes, and Southeast regions of the United States. The company supplies petroleum products to approximately 4,400 Marathon branded retail outlets and 1,600 Speedway SuperAmerica (SSA) stores. In addition to an extensive inland barge distribution network, Marathon owns, operates, leases or has interest in approximately 7,600 miles of crude and refined product pipelines.

Supporting an ArcView user base

Roger Holeywell, an advanced senior geologist in Marathon's Houston office, helps provide GIS and remote sensing support for Marathon's large internal user base. Holeywell's department is a long time LizardTech customer, having used GeoExpress for many years to create or modify images in the wavelet-based MrSID format for use in the company's many mapping projects.

Why MrSID? For Marathon, there are two main reasons. First, much of the public domain data available in the United States is only available in MrSID format. For example, like most companies in the petroleum industry, Marathon is a heavy user of public domain imagery available through the U. S. Department of Agriculture's NAIP (National Agriculture Imagery Program) project. Each year, the USDA’s Farm Service Agency acquires detailed aerial images of the United States to support crop and commodity programs. The agency makes the imagery available to the public in the form of wavelet-compressed county mosaics at 1 or 2 meter resolution either in natural color or color-infrared band combinations.

Cropped region from a county mosaic showing the Mimms Creek Field near Interstate 45 between Houston and Dallas. Marathon is one of several companies active in the Mimms Creek Field area.

"There are about a hundred counties in the U.S. where Marathon has some type of activity or interest," says Holeywell. "For those areas we provide our users with the last several annual cycles of NAIP imagery plus the corresponding raster topo map image mosaic." Specifications for NAIP require that the imagery be delivered to customers in MrSID format. Another example of public domain image data used by Marathon are the Geocover Landsat mosaics which are produced and distributed by NASA and provide a nearly cloud-free composite coverage of the entire world. These are downloadable as MrSID files from the John Stennis Space Center web site.

Besides public domain data, Marathon also buys commercial satellite data from QuickBird and IKONOS as well as occasional custom, project-level aerial survey photography. These images are converted from their source formats to MrSID to meet the requirement of being able to deliver the data to users in remote offices who need to have the smallest possible file sizes to deal with.

The second reason is that the MrSID format is well-supported by the client side applications. “We have a combination of GIS and non-GIS users who need access to the imagery” says Holeywell. “Our GIS users are all using the ArcGIS Desktop applications ArcView or ArcInfo, which have built-in support for the MrSID format. The non-GIS users usually use one of the free viewers which they download directly from the LizardTech website or install from our in-house software catalog. There are obviously other wavelet-compression formats available but keeping a single standard format when possible makes things a little simpler for our users.”

Marathon uses imagery from QuickBird and IKONOS for construction monitoring. Shown here is a satellite image of Marathon's liquid natural gas plant on Bioko Island, Equatorial Guinea, in west central Africa.

Putting massive imagery into common workflows

In the last few years higher imagery resolution, wider use of color, and larger frame sizes have meant that GIS departments have to manage dramatically larger file sizes. "Imagery users are always looking for more detail in their imagery, often without being aware of how large the files can become," says Holeywell “and high quality image compression has become a virtual necessity.”

Marathon also has a frequent need to be able to produce image subsets which are small enough to be emailed to clients, consultants, and contractors. In these cases, one of the time-saving features in GeoExpress is the ability to select cropping boundaries onscreen rather than finding and typing in coordinates. In GeoExpress the required area subset can be selected interactively and the compression and cropping done in a single processing run.

Finally, Holeywell also uses GeoExpress' ability to mosaic and compress in one operation. "We recently had 167 separate QuickBird tiles in individual GeoTIFF files that had to be temporarily stored on a standalone external hard because of their size. To make these more manageable for our internal ArcView clients we mosaicked and compressed all of the tiles into two seamless MrSID mosaics in two GeoExpress processing jobs. The resulting output files were small enough to be placed in the Asset Team’s normal data directory and the mosaics were much easier for our users because they didn't have to import and keep track of 167 tiles in ArcView." Holeywell says that he’s found that a trick for improving GeoExpress processing time is to split the input and output loads by placing the source files on an external USB drive and then directing the output file to the PC’s internal hard drive.

Enbridge Energy

Enbridge U.S. is a wholly owned subsidiary of Canada's Calgary-based Enbridge Inc. Headquartered in Houston, Texas, Enbridge U.S. transports crude oil, liquid petroleum and natural gas in the Midwest, Mid-Continent and Gulf Coast regions of the United States, and operates natural gas midstream businesses, including gathering, transmission, processing, treating and marketing subsidiaries.

Addressing inefficient movement in the field

Jason De Leon is a field designer in Enbridge's Pampa office outside of Amarillo. Along with his colleagues in two other nearby cities, De Leon creates imagery for field personnel working on a pipeline system covering 5108 square miles in seven counties in the Texas Panhandle and western Oklahoma. The pipeline in this region is located on private property, and right-of-way easements are leased or purchased from landowners for the lines, meter station sites, launcher and receiver sites, and other infrastructure. There are also compressor stations and gas plants where Enbridge employees process the natural gas. According to De Leon, "Construction is constant and can take place just about anywhere within these counties."

Shown here is an infrared aerial at 50 percent transparency combined with map data indicating section and block, plant (Briscoe), meter (Sophia) and pipelines. Enbridge field workers rely on combined raster and vector data to find their destinations quickly.

Along with the Houston office's repository of MrSID NAIP data that covers the entire state, De Leon uses 1- to 3-meter-resolution satellite imagery from Texas Natural Resources Information System (www.tnris.org), which varies from black and white to color to infrared. De Leon puts imagery created in ArcMap on a shared network drive so that field workers in his own region and users in the Houston office and other parts of the state can all have immediate access to it via ArcView or even ArcExplorer.

"We used to navigate by paper maps in the field," says De Leon, "which was a slow and frustrating process. Often our field people were given geocoordinates for their destinations, but those coordinate were not on the map. Also the maps made by the Texas Department of Transportation did not necessarily show all the roads that we have up here. Crews spend a lot of time driving around in circles. You'd get instructions like, 'Go to the windmill that's losing one of its blades and turn right, then turn left when you see three cows.' That's how bad it was getting to be."

An Enbridge employee collects GPS points while viewing a map of the area on a handheld device.

Now, with county imagery loaded into ArcPad on a handheld device, personnel in the field can type in the coordinates of their destination, then locate themselves on the device via an accompanying GPS, which displays both their position and their destination on the image layer. That way they can drive directly to the target location. "Pipelines are also on the map," says De Leon, "so with the imagery layer engaged you can see where the pipeline crosses a road. It takes our field workers less than a quarter of the time it used to take them to find a location. This is especially useful for new workers who might not know the area."

In this image an Enbridge pipeline is shown supported by an infrared aerial (set to 50 percent transparency) along with the computer's GPS location at the beginning of the pipeline run (red ciricle with cross in center).

Tools for image processing

In order for the geocoordinates to be meaningful in De Leon's geographic region, the imagery must be reprojected; that is, the geocoordinates and other georeferencing information accompanying the image must be translated from one coordinate reference system (CRS – sometimes also called a spatial reference system or SRS) to another. "The aerials in our Houston office come in at a standard coordinate system setting of NAD 83 UTM Zone 14," says De Leon, "but up here we need it to be in State Plane NAD 83 Texas North Feet."

De Leon says his office spent weeks looking at the various solutions available for working with compressed imagery and only received positive feedback on GeoExpress. Besides the basic function of encoding imagery to standard image format such as MrSID used throughout the geospatial industry, GeoExpress also performs image processing or "manipulation" tasks, including reprojection, cropping, area of interest encoding, and color balancing. For De Leon's workflow, these other functions are where GeoExpress plays its most important role.

"Everything we were told it could do and beyond, this product does for us," says De Leon. "By reprojecting this imagery with GeoExpress, we've saved literally tens of thousands of dollars over what it would have cost to have each county separately reprojected by a contractor. We also save a lot of money using GeoExpress to crop mosaics so that the black zones along the edges of mosaicked images are reduced or even removed."

Besides reprojecting and cropping, De Leon's team puts GeoExpress' color balancing feature to innovative use.

An aerial image at 50 percent transparency combined with pipeline and meter locations.

"If we have a canyon that we have to go through, by adjusting the color just a little, this will show up better," says De Leon. "Or maybe there's a lake or some aspect of private property that we have to go around, or any other obstacle that might be in the way geographically. We could come up short if we don't accurately account for these kinds of things." Having maps combined with aerial imagery represents a huge advantage over paper maps, where these obstacles were not as obvious. But a lot of times a little color balancing will make them stand out even more, which again saves Enbridge time and money. Also, some workers find it difficult to read maps in a single color, like infrared, so De Leon can alter a color value, remove one whole color, or convert and save the image as grayscale as an alternative selection for people in the field.

Finally, De Leon says he likes GeoExpress' ability to convert other formats to MrSID. "For example," he says, "to save some money on some flyovers, we had the imagery delivered to us in a file format other than MrSID. We were able to import these into GeoExpress and convert them to MrSID files so they were then ready to import into ArcMap complete with geocoordinates."

Using GeoExpress costs Enbridge a fraction of what it would cost to outsource reprojection, cropping and color balancing. Furthermore, De Leon and his three colleagues do it all with a single "floating license". Although they're in three different cities, a single networked license can be used by any one of them when not in use by another. De Leon and his fellow mapmakers work on a schedule designed to give each of them the time they need to encode and manipulate imagery on the floating license.

A launcher/receiver site for "pigging" lines that are inserted to maintain clean pipes for natural gas flow.

But De Leon's reserves his biggest raves for the time GeoExpress saves field workers. "Having all the image and map data they need for a job in the palm of their hand saves field workers hours and hours on the road. And like we always hear, time is money. The faster we can get work done, the better off our company will be."