Use for questions which involve a GIS principle or theory and are software agnostic

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1answer
25 views

Regarding spatial relationships, what is the Dimensionally Extended 9 Intersection Model (DE-9IM)?

In plain English what is the Dimensionally Extended nine-Intersection Model (DE-9IM)? What is the meaning of each row/column in the matrix? How can I use that information to build a relation ...
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1answer
32 views

Locating Moon in Sky from Earth

I am working on project which need to find moon location from a specified lat, long on earth. So basically info I am having is Lat,Long and Timezone. Format of the moon location Info? So first in ...
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3answers
46 views

Which rule to follow for defining an intersection as an ordered pair of streets?

Explanation Sometimes, for the sake of simplicity or speed, I need to list a location as a pair of intersecting streets. Let's use Luckie Street Grocery Store in Atlanta, Georgia as the example for ...
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0answers
72 views

When to use DBMS instead of System Files for Spatial Data Storage?

I'm having trouble deciding when it is best to use a DBMS instead of System Files for storage of Spatial Data. Are there any specific guidelines and reasons for when one method is preferred over the ...
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2answers
74 views

Measuring tool shows different measurements for same building in two different map documents?

So I have two map documents with two different Coordinate Systems set for the layers but using copies of the same shapefile. Map 1: Coordinate System: ...
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0answers
43 views

Internet mapping UX design strategy: Separate desktop and mobile sites, or one site fits all?

I searched GIS.SE for "Desktop vs. Mobile" and didn't get anything helpful, so I guess I'll be the one to ask. Question: With respect to Internet mapping applications, is it better to have separate ...
5
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1answer
353 views

Terminology problem - Raster vs Grid vs Lattice

I have a question about GIS terminology - what is the difference between grid and raster and grid and lattice - in theory?? I thought, that raster is regular network and value is in the cell and the ...
1
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1answer
793 views

How to calculate the size a bounding box?

What formula could I use to calculate the size in Kilometres of a bounding box based on a given Southwest latitude/longitude and a Northeast latitude/longitude points? The bounding box format is ...
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1answer
48 views

Do transfer edges add to the distance cost of a route?

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 ...
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0answers
237 views

Linear Referencing Methods: Station Equation origins

DEAR PEOPLE FROM THE FUTURE: Here's what we've figured out so far… I am working in the pipelines field, and I get in touch with the concept of the linear referencing methods, specifically with ...
8
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4answers
129 views

Selected Literature on coordinate transformations?

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 ...
2
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1answer
33 views

Is it better to define object properties or layer properties?

I have a question, but it is difficult to phrase. I am picking up GIS methods as I go, and I have run into this problem frequently. Please excuse me if I am in the wrong place. When organizing ...
2
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1answer
130 views

What are the geometric principles and GIS techniques that I can use to generate a postcode coverage of my city at street scales?

Postal codes of Brazil and another countries are oriented to distribution logistics, and improvement of reliability in writing the postal addresses; but without much concern for the spatial ...
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1answer
180 views

How to store route names of a stop belonging to multiple routes

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 ...
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3answers
333 views

Does Earth's magnetic field affect any datum definition?

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 ...
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7answers
1k views

Spatial reference for dummies?

Can anyone recommend a good reference or tutorial that explains the principles of spatial references, projections, and coordinate systems? We are a small team of programmers working with GIS ...
6
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1answer
113 views

How can I generate a range of pantones for a map?

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 ...
4
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0answers
246 views

Topology - To be, or not to be, that is the question [closed]

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 ...
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3answers
168 views

Location storage and query algorithms. How do they work?

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 ...
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3answers
359 views

How can Flocking Algorithms be used in GIS?

The first flocking algorithm was written by Craig Reynolds in 1986. A recent browser implementation can be found here. ...
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3answers
1k views

Is the Fourth Dimension used in GIS?

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 ...
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5answers
3k views

Algorithms for matching segments

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. ...
68
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14answers
16k views

What Makes a Map be classed as Badly Designed?

A poorly designed map can not only look visually unappealing, but can convey the wrong message, which could lead to bad decisions being made. I would like to ask people to post examples (that are in ...
163
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48answers
41k views

What Makes a Map Beautiful?

Often times when we make maps it is based on our subjective interpretation of what is aesthetically pleasing. I would like if people posted examples of beautiful maps, displaying any phenomena in any ...
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15answers
20k views

What are Definition, Algorithms and Practical Solutions for Concave Hull?

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 ...
129
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11answers
32k views