Insights Into Remote Site Conditions Without Leaving Your Desk


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Gain Insights Into Remote Site Conditions Without Leaving Your Desk: Industry trends, tips, and practical uses for aerial imagery and geographic data from First Base Solutions, the experts who brought you MapWarehouse.

Thursday, November 3, 2016

Rarely Asked Questions - Isn't There Anything Newer?

The data isn't old, it's established


Fifteen years isn't long in geological time. So is it really worth your time to look for updated mapping if you're only interested in geological features or other map data that won't change at all in your relatively short human lifetime? Probably not.

One question we often get from customers is, "Don't you have anything newer?"

In some cases, that's an excellent question. We update large portions of our aerial imagery every year to keep up with demand for new data, especially in suburban areas where land development is taking place. In the built environment, the imagery will be different every single year, so it's worth the effort to fly the same areas over and over.

The same is true for many types of "cultural" features such property line boundaries. Not every parcel changes every year, but within our large database covering all of Ontario, enough parcels change to need scheduled updates to maintain the relevance of the information a few times a year.

Brampton in 2008 and 2012

Not so, however, with other types of mapping. Apart from aerial imagery, one of our most popular data products is elevation mapping. Back in 2002, we used photogrammetry to calculate the elevation of ground features in our aerial imagery to create a grid of spot heights across the Golden Horseshoe, then marked out ridges, valleys, road edges and so on to help refine the model. CAD users call this a DEM, or Digital Elevation Model.

We also used this model to create elevation contours at 1m intervals for Microstation users. Same info, different packaging.  The elevation values of the spot heights are precise to several decimal places which is isn't very easy to interpret visually. We mathematically found the mid-way place between every pair of neighbouring points where the elevation would be a whole number, then connected the dots to draw lines of equal elevation. Contour lines are typically found on topographic mapping as parallel lines or concentric circles.

DEM Spot Heights with Break Lines (left) & 1m Interval Contour Mapping Created From It (right)
Since our DEM and contour mapping is looking at bare earth topography, and the lay of the land doesn't generally change, there's no reason to reject the data based solely on its age! Surveying equipment and techniques have changed over the years, definitely, but the topographic information found on good maps drawn 100 years ago will still be accurate.

There are a few exceptions. Activities that change the landscape such as mining, dam building, and urban expansion would require an updated map if those activities took place at your area of interest since the DEM was produced in 2002.


To learn more or to purchase mapping data, please visit www.firstbasesolutions.com