1
vote
0answers
71 views

Convert polygon data into extreme lon/lat coordinates using QGIS

I'm very new to QGIS. I have a shape file of census blocks and want to use the data to plot points within each boundary using Google Maps api. I figure the best way to do this is to find the extreme ...
2
votes
1answer
126 views

What methods exist for geohash of polygon?

GeoHash is an excellent method to code the latitude and longitude of a point into a string. It's concise, due to the use of numbers + letters, and the precision can be tuned adding characters at the ...
0
votes
1answer
62 views

calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
0
votes
1answer
143 views

How to obtain the maximum/minimum longitude and latitude for a polygon?

I have the MSA/CMSA shape file which contains 274 metropolitan areas. How do I have to obtain the maximum/minimum longitude and latitude for an area? So, it's like drawing a box right outside and ...
2
votes
1answer
128 views

Compute the area of a given polygon (in vector format) lying between specified lines of latitude

I have species distributions (in vector format) and I would like to calculate how much of the area for a given species distribution is within certain lines of latitude, such as temperate and tropic ...
0
votes
1answer
78 views

Openlayers selection

Is it possible to select a polygon from a predefined Lat & Lon programmatically? eg location point: x='1234' y='5678' intersects polygon '1234', therefore SELECT POLYGON '1234' So far I have ...
0
votes
0answers
152 views

Offset a Polygon defined in Lat Lng points by a given distance of miles or km

I am trying apply a positive offset/buffer (enlarge a shape equally from the borders) to a polygon that is made up of a series of latitude/longitude coordinates by a distance that is defined in either ...
3
votes
3answers
386 views

How do I sort polygons by their latitude?

We have a set of polygons which we would like to sort and number according to their latitude. This will make it easier for local authorities to relate to the numbers of the objects. I have looked ...
2
votes
1answer
521 views

How can I get the corners of a polygon in latitude and longitude?

How can I get the corners of a polygon -a square/rectangle, to be precise- in latitude-longitude format by using its geom value -or some other way, perhaps-? Thanks.
5
votes
2answers
2k views

Converting Longitude and Latitude Coordinates to Square Miles?

I have a set of Long and Lat co-ordinates making up a five point polygon which I have converted in excel using the following formula: ...