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Oct 11 2011

Virtual Site Visit

I just got back from a beautiful trip to Bernalillo, New Mexico for a field visit on the Rio Grande River to look at an erosion site.  I have always enjoyed going to a site that I will be working on, and it always proves to be very beneficial to a project to actually have been there.

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Something that I have added to my work flow that continues to improve in its benefit to projects is a virtual site visit before, and after, I actually go to the real site.  Is this something that you do? If so, what does that look like for you?

Here are some of the tools I use.

The Tools

Google Maps

Google Maps

This is a quick and easy places to start.  It’s free, easy to use, and has a lot of great info.  Beyond the aerial image and map the Google Maps Street View can be very helpful if it’s available.  There are also additional user photos that can provide additional views of an area.  Of course, the closer to an urban area the better.  The ability to create your own maps with custom notes, places marks, etc. and then share that with others is can also help during a job.  You have to have an account with Google to do this though.

Bing Maps

Bing Maps

Basically the same thing as Google Maps including maps, aerials, and user photos, but I always check to see if there is Birds Eye imagery for a place I am travelling to.  The ability to look at your site from an oblique aerial perspective from the North, South, East, and West can be very helpful in getting a feel for a specific location.  Again, the closer to civilization the better.

- Google Earth

Google Earth has almost the exact same aspects of Google Maps, but it requires you to download the application onto your computer.  While there is one extra step, it is well worth it for what is essentially a free GIS like software application.  I run the Pro version, so I have some additional capabilities, but either way Google Earth is a must have for virtual site visit.

The historical imagery is an additional option compared to Google Maps, and can be helpful to review any significant changes to a site over the past 10 – 20 years.  You can also load your own geo-referenced aerial imagery if you want for additional data all in one place.

In urban areas there is an ever growing amount of 3-D buildings, bridges, and trees, making areas more realistic and data rich.  Google Earth also drapes the imagery onto terrain data to give it the 3-D look.  While this doesn’t usually work great around rivers, it is still helpful to see the relief.  For the U.S. the terrain data is from the USGS and is similar to what the USGS Topo maps are based off.  With the Pro version you can use cut a profile or cross section line right in Google Earth.

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Google Earth comes with a decent database of geospatial data, but the real power of is what you can import into Google Earth.  Essentially any geospatial data (which could literally be anything if tie it to location) can be imported into Google Earth and then saved out as a .kmz or .kml and shared with others.  So you can import whatever data you have specific to a site and view it with all of this other information.

Most organizations also provide .kmz files that connect you to even more information that is already publically available, but now you can access it by location within Google Earth.

I often need to look at USGS stream gage data, which you can do on from several places.  They also provide a file you can load into Google Earth and it dynamically links to the USGS data online.   So you can quickly find the gage you want and view trends across the U.S.

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I also have files that show State Plane Zones, show UTM zones, link to the National Hydrography Dataset, display FEMA flood map data, display USGS topographic maps, and some other overlays I occasionally use.

So before I ever step foot on a site, I will have spent some time getting a feel for what to expect, looking at the area from above, and finding additional data that may be helpful.  While not a complete replacement to actually being there, it has always improved and fine tuned what I am doing when I arrive at the site.

There are also some additional pieces of data and other tools that I use, but they are not as quick and easy to obtain and use.  I will go over some of the extra options available next if you’re interested in more.

3 comments

  1. Jessica Ludy

    These are really great ideas– I also use bing maps and google earth, though I hadn’t considered checking out the USGS stream gauges before a site visit.

    Before I go to specific sites, I use google earth to look up and downstream of the whole river system for bottlenecks, land use patterns, and other flood control measures that might affect local hydrology.

    Site visits for my research, however, are often at a “30,000” foot view as much of my interest lies in regional flood management policies and strategies in other countries or cities.

    Before site/country visits–I usually look up the cultural, flood, and water management history of a place so that I can orient myself and learn the context under which the existing system and settlement patters developed. In the Netherlands, for example, much of this land used to be below the sea.

    Sometimes you can find this information under local emergency response departments, flood control districts, newspaper articles, and even… wikipedia.

  2. Bill McDavitt

    The FEMA Map Service Product Catalog (http://msc.fema.gov/webapp/wcs/stores/servlet/StoreCatalogDisplay?storeId=10001&catalogId=10001&langId=-1&userType=G) is another website I’ve used before doing site visits. I can get the 10, 50 and 100 yr flood record and typically I can get a general sense for what the longitudinal profile looks like at the end of the document.
    Also, the FEMA National Hazard Flood Layer kml
    (https://hazards.fema.gov/femaportal/wps/portal/NFHLWMSkmzdownload) can come in handy as certain areas in the nation have good coverage with respect to cross sections and base flood elevations.

  3. Bill McDavitt

    This table has slowly grown over time, but it still has large swaths of areas that aren’t covered. Nevertheless, it’s worth a peak if you are interested in finding out if any regional hydraulic geometry curves have been developed for your project area.
    http://www.nrcs.usda.gov/wps/portal/nrcs/detail/?ss=16&navtype=SUBNAVIGATION&cid=nrcs143_015052&navid=120160210000000&pnavid=120160000000000&position=Not%20Yet%20Determined.Html&ttype=detail&pname=Regional%20Hydraulic%20Geometry%20Curves%20|%20NRCS

    Apologies for the long URL – hopefully it will work.

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