# Tagged Questions

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

561 views

### Calculate 'Rectangle' Coordinates Given 2 Points and width [closed]

I want to create a rectangular polygon using two points as guides. So let's say a journey starts in Egypt and ends in London, my polygon should have 4 points: 10 miles further from London than Egypt ...
960 views

### Find the nearest point on a line

I have a line that exists between two latlon positions, and a point on a certain latlon position. What I want to know is what the nearest point on that line is (in respect to the other point). So a ...
14 views

### strange misplaced markers on the map [duplicate]

Possible Duplicate: place markers on the outline of a circle in google maps I used word Strange because I'm not expert in this area, and it really looks weird to me. I've already asked a ...
715 views

### How to place markers on the outline of a circle in google maps?

I have the center of a circle and it's radius and I need to place variable amount of markers on the outline/stroke of the circle. The distance between this markers should kept same, so if I have 8 ...
374 views

### Proper use of Modulus “%” operator in ArcMap [closed]

Objective: Gather pour points to define a specific-sized watershed. In this case, 1000 pixels. (for this thought exercise, watershed is to mean any point that flows through a pour point, regardless ...
2k views

### Doing Math calculations within ArcMap Dynamic Text?

Is it posssible to perform any math on ESRI ArcMap dynamic text? For example I have the area of a SDE park layer's SHAPE.AREA, but it is in m2 because the layer is in NAD_1983_UTM_Zone_17N. I want ...
593 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. ...
5k 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 ...
194 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 ...
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. ...
12k 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 -0.5482298619861881,53....
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### 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 ...
181 views

### Understanding location storage and query algorithms?

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 ...
597 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 ...
4k 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 ...