Transfer edges are commonly used in a network dataset to carry a time cost in one direction only (either to-from or from-to). This is fine if the impedance used is time, i.e. find the route that will ...
I am working in the pipelines field, and I get in touch with the concept of the linear referencing methods, specifically with station equation method. I had to do research about this method, I'm ...
I am looking to hone my skills in the theory and the mathematicas involving the projections systems, projection transformations ( from xy to uv, φλ and vice versa). Can you share the ...
I've been reading the ArcGIS help files on route analysis to gather more information on what attributes are stored with Stops. Maybe I've stared at the screen too long, but I cannot seem to understand ...
I had an interview last week. One very interesting question was "does earth's magnetic field affect any datum definition?" I was sure it does not for geocentric datums. But I thought maybe the ...
When I am given a map (or make one...) I often like to get an idea of the range of colours present. One thing this does is it allows me to quickly visualize contrast (helps build maps for colour blind ...
Topology, I mean "real" topology, is not a new concept and it's available since a long time in GRASS gis. I won't speculate the reasons myself but, after a long period of spaghetti model ...
One of the most important aspects of a GIS-equipped database is that it provides the user with the capability to quickly query for all points within some arbitrary geographic area that match some ...
The first flocking algorithm was written by Craig Reynolds in 1986. A recent browser implementation can be found here. ...
Whilst working with OGR, I came across the following field used define a geographic dataset: COORD_DIMENSION The spatial dimension (2, 3 or 4 dimensional) of the column. Whilst I've used 2D and 3D ...
What are the best algorithms to match segments? I'm trying to match corresponding segments from two map sources, one less accurate but with segment names, and one more accurate without segment names. ...
Convex Hull A convex hull of a shape is defined as: In mathematics, the convex hull or convex envelope for a set of points X in a real vector space V is the minimal convex set containing X ...
What's the difference between a projection and a datum?