Tuesday, November 25, 2014

Finally getting good results using ArcScan for some HGIS work with Fire Insurance Plans


You cannot use raster cleanup on BMP formats. You can only use it on IMG, TIF, and GRID format files.

Shortest Path in QGIS

This Road Graph QGIS plugin is so amazingly simple to use, and yet so powerful in creating shortest path distances along road networks.


Saturday, January 11, 2014

University of Ottawa publishes 1' to 1mile NTS maps

The University of Ottawa is making available their collection of scanned historical NTS sheets. The maps currently don't have a front end, but the naming convention of each of the files makes it quite easy to find the sheets you are looking for. The maps can be found here.

The University of Toronto also has a number of historical NTS sheets, and pre-NTS topographic maps at various scales. Those are available online here.

Thursday, January 10, 2013

3D model of a real forest from airborne LiDAR - YouTube

Fantastic video tour through a French forest through a 3D model from airborne LiDAR
The thesis, available here, describes the methods and data used for the video.

Thursday, October 18, 2012

Missing Minching street. An error or a trap!?

In georeferencing a Fire Insurance Plan from 1909 today one of my students was having a really hard time matching Minching street with DMTI's Road Network file. DMTI has classified the road as a "5" in their categories of roads, which translates to a "local road".See the image below.
1909 Goad Fire Insurance Plan with CanMap Routelogistics (click to enlarge)

Google Maps view of the area. (click to enlarge)

The problem is, Minching street existed on the 1909 map and on the DMTI file, but in a different location and with a slightly different spelling (Minging).  Overlaying Bing Maps we realized that the street actually no longer exists and was covered over by a building at the corner of Bay and Wellington streets. The building seems to contain the Design Exchange and Ernst and Young, according to google maps.(image on the left)  Google is, of course, not immune from adding phantom locations on its maps either, have a look at this blog post

What makes the addition of this road interesting is not only that the street  once existed, but that it existed in a different location.  About half a block west of where DMTI has Minching positioned, is the street in 1909. Our historical street data, compiled at the map and data library do not indicate the street ever existed prior to the 1890's.  

The image below indicates that Bing Maps do not have Minching street in their road network data.
DMTI Routelogistics overlayed on top of Bing Streets (click to enlarge)
Bing map images shows a building on the site (image below).

Bing Aerial image with the DMTI streets overlayed on top. (click to enlarge)

OpenStreetMaps do not have the street listed either, see below
DMTI Routelogistics overlayed on top of Openstreetmaps. (click to enlarge)
The question then becomes, is this an error in the DMTI data, or did they put this street in their database as a copyright trap?  Stay tuned for the answer once I get this question to them.

It would appear the National Road Network file from the Canvec product at Geogratis.ca does not contain Minching street either. See Below:

Marcel Fortin
GIS and Map Librarian
University of Toronto Map and Data Library

Tuesday, October 16, 2012