ArcGIS Earth: Google Earth, GIS style

For most GIS professionals, Esri’s new ArcGIS Earth will replace the soon-to-be-discontinued Google Earth Enterprise. I take a tour through the new software, which is much like Google Earth with a few added features. Plus: Q&A from our December UAV webinar.

In early 2015, Google announced that Google Earth Enterprise is being deprecated. In the software world, deprecated means the software is heading towards obsolescence and the vendor isn’t going to develop it further.

Google’s announcement stated that Google Earth Enterprise was being deprecated as of March 20, 2015, but will be supported through March 22, 2017. According to Esri, Google will continue to provide map and location services APIs as well as content.

Here comes Esri, introducing ArcGIS Earth.

At the Esri User Conference last summer, Jack Dangermond announced Esri is working on ArcGIS Earth. Last week, Esri announced the introduction of ArcGIS Earth 1.0. You can download ArcGIS Earth for free.

The opening screen looks a lot like Google Earth, but clearly with an Esri touch via the toolbar in the upper left corner.

You can connect to ArcGIS Online and access its library of data, or import SHP and KML data (no TIF/TFW import, though).

Here are the convenient editing and querying tools (measure).

I imported a KML file containing an orthophoto I created from a UAV flight. Sorry for the orthophoto offset (darned horizontal datum thing).

As it stands now, ArcGIS Earth 1.0 is much like Google Earth with a few added features. However, based on what I perceive Jack Dangermond’s mantra to be, ArcGIS Earth is going to evolve into a powerful mapping tool and platform for consumerizing feature-rich GIS data, much like Google Earth did in the past 10 years, but in a much more GIS way. I look forward to that.

December’s UAV webinar

Speaking of imagery, Google Earth and UAVs, in December I participated in a webinar entitled “Introduction to Using UAVs for Mapping” along with my colleagues from Applanix and C-ASTRAL. If you missed the webinar, you can still view it by signing up here.

It was a solid, 60-minute discussion about the basics of mapping using UAVs. We had a few questions that we didn’t have time to address during the webinar, so I provide answers below. Also, I added some questions that may have been answered, but deserve mention again.

How significant is the quality of GNSS sensors for UAV mapping performance?

In my experience so far, you need precision GNSS measurements either in the air or on the ground if you want high-accuracy results. If you want to use a consumer UAV that has a consumer GNSS receiver in it, you’ll need to use more ground-control points that are mapped with high-precision GNSS receivers. On a wide-open 150-acre site (think agriculture field), that means setting 10-15 ground-control targets. On the other hand, if your UAV has an RTK GNSS receiver in it, you can get by with very few ground-control points. The type of topography also has a significant impact. For example, heavy tree cover, water bodies and other homogenous terrain (such as snow) make it more difficult for image-processing software to process the images.

How accurate can volumes be obtained on stockpiles?

I plan on running some tests and compare volumes computed using terrestrial measurement techniques vs. volumes computed by low-cost UAV images. Based on my experience, I’m willing to wager that the results will be very close.

What are the reasonable accuracies achievable with UAV mapping these days?

With a low-cost UAV (12MP camera), I’m collecting images with a 2-cm/pixel resolution. Horizontal accuracy (with RTK ground control points) is 30 cm or better. Thirty centimeter (30 cm) elevation contours are achievable, and possibly better than that. I’m still exploring how far we can push low-cost UAVs.

Can we use a UAV with our own GPS-RTK base station?

The best use of your GPS-RTK base station is to use it to set RTK ground control for image processing. It’s likely not feasible that you can send corrections from your GPS-RTK base to the UAV unless the UAV is specifically designed to accept those corrections.

Can you tell us the benefits of fixed wing vs. rotary UAVs for mapping work (such as considerations of weather conditions and the benefits of a gimbal-based camera versus a non-gimbal camera typical in fixed-wing UAVs)?

A fixed-wing UAV can cover a much greater area per battery than a rotary UAV, but if you’re located in the U.S., you are restricted to line-of-sight operations. That severely limits the value of a fixed-wing UAV. Fixed-wing UAVs also require a much larger landing area and are trickier to land. It takes much more training to land a fixed-wing UAV than a rotary UAV. I can’t answer your question about gimbal vs. non-gimbal, except that the rotary UAV that I operate has a gimbal for dampening the effects of vibration. With it, vibration doesn’t seem to be an issue.

In forestry, one of the real challenges is stitching the photos together. Did I hear right that RTK will ensure stitching will be greatly improved?

In my limited experience with flying over heavy tree canopy, the best way to handle this scenario is to fly with a heavy overlap (such as 90 percent) or fly at a higher elevation. Since most commercial authorizations in the U.S. limit flight elevation to 200 feet, there’s not a choice to fly higher, so you must fly with a higher overlap.

Eric, could you change the camera to a near infrared camera?

Mine is a consumer UAV, so there’s little support for customization unless I want to really tear it apart myself. There is some after-market support for NDVI and NIR sensors on consumer UAVs, but I’m not knowledgeable about the quality of those. I think that after-market and manufacturer support of various sensors (cameras, NIR, NDVI, lidar) will become more popular on higher-end consumer UAVs.

Eric, the contours seem to capture the curbs in the upper right. Is that correct?

Correct, it’s pretty impressive for a consumer UAV. Granted, I set a dozen or so RTK ground-control points on a 5-acre site, but I’m pretty sure I could cut that in half and achieve the same result. By the way, I should smooth the elevation contours next time.

What software was used to create DEM?

I used Agisoft PhotoScan Pro.

Currently, the use of UAVs seems to be limited to a relatively small project area and required line of sight. Within the natural resource sector, what is the critical barrier at this point to expanding the project size and thus the range of flight — is it technology or air traffic regulations?

In the U.S., the limitation is a regulatory one. The FAA requires visual line-of-sight at all times when operating the UAV. The FAA is testing beyond visual line-of-sight (BVLOS), and we hope that someday BVLOS rules will be issued for commercial operators. For now, you are correct in that UAVs are limited to relatively small areas.

How do the new FAA drone registration rules affect commercial mapping?

According to the FAA, you need to apply for a Section 333 Exemption and CoA (Certificate of Authorization or Waiver) from the FAA to fly UAVs for commercial purposes. This applies even if you want to fly above your own land or even if you don’t charge for flying. If you fly for any other purpose than as a hobby, it gets complicated very quickly.

Look for more content on UAVs in the near future. I’m pushing consumer UAVs to the maximum to see what we can reliably expect from them.

See you next month.

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