Software Review: All Topo for Quadrangle Maps
Professional Surveyor Magazine - November 2010
J. Craig Brewer, PLS
My experience working with USGS
quadrangle maps has been limited mostly to scaling prints or using image files in a viewer or in AutoCAD, because the file sizes make importing and screen navigation slow. Plus, combining topographic data with other drawing data usually requires digitizing over the image and then freezing the image layer, which can be a very time-consuming process that causes me to think of other, more productive things I could be doing.
changes this. It’s a software package consisting of USGS quadrangle maps and the AllTopo Topographic Map Viewer that takes working with quad maps to a new level. The iGage Mapping Corporation has created a product that transforms common topographic maps into interactive digital models and added the tools that allow you to quickly find the locations of interest, extract the data you need, annotate the map, and print or export for use.
When launching the program I was asked to select a state set to open (state sets can be purchased individually and added at any time). I was impressed with how quickly the map loaded and how easy it was to pan around the map. First I created a project and glanced through the menus and toolbars. I also used the iGage website to guide me through the software. The video tutorials are some of the most detailed I have seen. They go chapter by chapter through each section. It was well worth the time spent learning where each command is located and what the software is capable of.
There are several different ways to navigate the maps. You can search by location name, address, coordinates, map name, or state overview (Figure 2
). You can also use the scroll wheel on your mouse if you are already familiar with the area and know what to look for. All maps are shown at 250 dpi resolution from the base scans.
Several coordinate systems are supported by way of Nadcon conversions, including: state plane systems (also with HARN adjustments), military grid reference system, national grid, geographic, and UTM. Public land coordinate styles include: township, range, sections, fractional sections, and footage offsets. The view settings let you display two coordinate projections at the same time. You can also show the elevation, maximum slope, and computed declination for your cursor location. AllTopo provides a ton of information at your fingertips.
AllTopo puts an end to the days of searching through image files to find the one you need. When you need to move to an adjacent map, you can double click outside the current map, and it will load for you. I was really impressed with the speed of image regeneration and loading.
There are several different tools provided for measuring distance, area, elevation, and slope. Each has a setting dialogue box where units, projections, and other preferences can be set. I was a bit overwhelmed by the amount of settings, but once they are set, I appreciated the ability to control the data reported on the screen.
For distance measurement, one command is called the “measurement spike.” This allows you to set a reference position on the map that same way you would drive a stake in the ground and attach the end of a cloth tape to it. As you move the cursor around the screen, distance is given from cursor to spike.
The “bombsight cursor” allows you to trace an area of interest (Figure 3
). A window at the bottom of the screen reports the route distance and area in real time. If you traverse clockwise, the area is added. If you traverse counter clockwise, the area is subtracted. This allows you to add and remove areas within areas easily without the need to write each down and manually compute the area you are looking for. This one simple tool could save me from the digitizing exercise I described above.
I recall planning a photo control project several years ago that involved selecting target locations, researching NGS monuments in the area, and manually loading waypoints into a GPS receiver (Figure 4
). What took me several hours could have been handled in a fraction of the time with AllTopo.
AllTopo allows you to create waypoints and export then into a GPS receiver. It also allows you to search the NGS database for survey control in the area and provides links to the datasheets (Figure 5
). AllTopo imports field collected waypoints into the project database and displays them on the map. Using the Geo-
Link tool, you can attach digital photos. This is a great way to organize and store project data such as survey control, site visit notes, and project photos. While digital orthophotos are not included with the AllTopo package, they can be imported very easily.
AllTopo has taken “old school” printed quadrangle maps and created a highly efficient, digital, topographic database.
I encourage you to take a closer look at it.
About the Author
J. Craig Brewer, PLSJ. Craig Brewer, PLS is owner of Brewer Land Surveying in Savannah, Georgia. He has over 15 years of experience and is a licensed professional surveyor in Georgia and South Carolina.
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