The abstract study of topics encompassing quantity, structure, space, change, and other properties

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1answer
494 views

Recreating A Lat/Long Grid Using a Specified Formula

I'm trying to recreate the Gridded Mercury emissions 2000 (0.5 x 0.5 degree grid) designed by the Arctic Monitoring and Assessment Programme. The file is in ASCII format, but without any coordinates. ...
7
votes
3answers
3k views

How to find a point half way between two other points?

I'm working on implementing the OSM Mobile Binary format for map data, and because it uses a 16 bit delta for each point along a way, it cannot represent a way if there is a large distance between two ...
4
votes
3answers
188 views

Math module VS PostGIS

I have a simple (and maybe stupid) question for you today. I have to compute intersection points between GIS polygons and imaginary lines I draw thanks to a script of mine... And I wonder if it would ...
4
votes
2answers
2k views

How to “calculate” distance-to-ground of all 18 OSM zoom levels?

Assuming I'm building a 3D solution with the "world" being mapped to global geo-data supplied by OSM / Cloudmade... think http://www.webglearth.com but with completely different goals and use-cases. ...
6
votes
5answers
9k views

Calculate midpoint from a series of latitude and longitude coordinates

I've got a series of longitude and latitude coordinates which represent a building outline e.g. -0.5485381346101759,53.2285150736142 -0.5482220594232723,53.22842450827133 ...
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3answers
3k views

Calculating the distance between a point and a virtual line of two lat/lngs

Please refer to the example and corresponding image. I would like to achieve the following: provide two locations (lat/lng), which are shown below as A and B. From this, a virtual line would be drawn ...
8
votes
3answers
169 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 ...
11
votes
4answers
560 views

Math and Stat for GIS and Computing

I am planning to do an advanced program in spatial science and engineering. It states as a requirement in the program, that the student should have a through understanding in math and statistics. So ...
6
votes
1answer
3k views

RMSE between two rasters step-by-step

Can anyone show how to calculate the RMSE (root mean square error) between following two rasters step-by-step and discuss on the obtained results' min and max values, and how to interpret it. Thanks a ...
7
votes
2answers
2k views

Determine angle down to horizon from different flight altitudes

I'm a pilot, not a GIS expert. What I need is a formula or a web site that I can supply the variables to answer my question. I need to know the angle down to the horizon from different flight ...
2
votes
1answer
367 views

How do I calculate curvature using GIS co-ordinates [closed]

I have GIS data for which I would like to calculate where curvature is present. Anyone has done this before, please help.