Posts Tagged ‘10m’

The Accuracy and Precision Revolution: What’s ahead for GIS? (Nighbert via ArcUser)

Wednesday, April 7th, 2010

acc_precis_5-lg

[Editor’s note: “As we try to integrate highly resolved data into existing GIS, the errors in legacy data will become more apparent.” Jeff outlines the problem through his experience at the BLM in Oregon. Jeff is also responsible for early “bump mapping” of digital terrain models (DEMs).]

Republished from the ESRI ArcUser Winter 2010.
By Jeffery S. Nighbert, U.S. Bureau of Land Management

The ability to obtain precise information is nothing new. With great patience and skill, mapmakers and land surveyors have long been able to create information with an impressive level of accuracy. However, today the ability to determine and view locations with submeter accuracy is now in the hands of millions of people. Commonly available high-resolution digital terrain and aerial imagery, coupled with GPS-enabled handheld devices, powerful computers, and Web technology, is changing the quality, utility, and expectations of GIS to serve society on a grand scale. This accuracy and precision revolution has raised the bar for GIS quite high. This pervasive capability will be the driver for the next iteration of GIS and the professionals who operate them.

When I say there is a “revolution” going on in GIS, I am referring to the change in the fundamental accuracy and precision kernel of commonly used geographic data brought about by new technologies previously mentioned. For many ArcGIS users, this kernel used to be about 10 meters or 40 feet at a scale of 1:24,000. With today’s technologies (and those in the future), GIS will be using data with 1-meter and submeter accuracy and precision. There are probably GIS departments—in a large city or metro area—where this standard is already in place. However, this level of detail is far from the case in natural resource management agencies such as Bureau of Land Management (BLM) or the United States Forest Service. But as lidar, GPS, and high-resolution imagery begin to proliferate standard sources for “ground” locations, GIS professionals will begin to feel the consequences in three areas: data quality, analytic methods, and hardware and software.

Continue reading at ArcUser . . .

Adding new rivers and lakes to 10m Natural Earth in North America

Tuesday, January 19th, 2010

Tom and I have been busy adding 4 times the rivers and 3 times the lakes we had for North America. This adds in many “missing” hydro features that one might normally find on a 1:10,000,000 hydrologic reference map.

Why were they missing from the first version of Natural Earth? It’s hard to wade thru 1:1,000,000 features to figure which to add and an even tougher job to attribute them with the correct name and scale ranks. There’s another factor: these extra features are great if you’re making a watershed map, but can be a little noisy when used as a background layer in say a political reference map.

Cody Rice, now of the EPA but formerly of the Commission for Environmental Cooperation (CEC) send along an amazing link last week. The CEC is a joint agency between the United States, Canada, and Mexico. Specifically: USGS, Natural Resources Canada, INEGI-Mexico. Each country contributed base data for a 1:10,000,000 digital atlas. The data is available in many popular formats and is in the public domain. Better yet, it includes GIS data attributes like river name!

We’ve compared with our existing Natural Earth linework and identified which features were missing. For those we’re adding, we’ve adjusted the new linework a nudge here and there so it lines up with SRTM relief and our existing linework. We’ve also gone thru and created lake centerlines and applied scale ranks to all in three new steps (10, 11, and 12). We have some final polishing but will be releasing, along with some slight adjustments to the original data, by the end of January.

Do you have time to donate? Unlike ranks 0 to 9 (the original data), this new data will NOT come tapered. We’d like it to be and can show you how.

Know of a similar, attributed with name, 1:10,000,000 regional dataset we could adapt into Natural Earth to build out our coverage? Please let me know at nathaniel@kelsocartography.com.

Preview images below:

Red = new at rank 10. Blue = new at rank 11. Black = new at rank 12. Grey = old at ranks 0 to 9.

Click images to view larger sizes.

hydro_west_coast

hydro_mid_west

hydro_east

hydro_mexico

hydro_alaska

hydro_yukon

hydro_quebec