Tagged Questions

On a map, a closed shape defined by a connected sequence of x,y coordinate pairs, where the first and last coordinate pair are the same and all other pairs are unique.

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1
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1answer
130 views

How to limit Create Fishnet extent by mask & carry over attributes?

I have a 5km polygon grid of an area which is not a standard square/rectangle, it is in fact a rough ovoid made up of around 500 5km2 cells. What I want to do, eventually, is have a 100m polygon ...
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0answers
42 views

Split polygon into four with respect to single point

Some days ago one of my colleague came to ask me a query related to Geometries. The situation is as....There is one Polygon(suppose a city polygon) and there is one point(suppose user's current ...
0
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2answers
96 views

How to generate polygons upto the edge of other polygons?

I am doing some work on a pipe network (blue lines) and I am trying to attribute the information about the street to the pipes. I have 2 polygon layers one of the blocks (green hatch) and one of ...
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0answers
43 views

Split/Erase/Differentiate polygon by polygon within a same layer

Is it possible to split a polygon with a polygon within the same layer in QGIS ? As in the image, i want the Polygon 2 to be split & the pointed area has to be retained as a separate polygon. ...
1
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2answers
71 views

QGIS radius buffer question, can it be more circular?

Conundrum for the day, When I request a radius buffer in QGIS (Dufor). my buffer comes out as a 20-sided polygon rather than a true "circle". This has lead to some missed blocks when clipping ...
2
votes
1answer
247 views

Why does clipping a line layer using a polygon result in an empty shapefile?

I am using QGIS 2.2.0 and want to clip a line layer (roads) so that only those inside a polygon are shown. When I do this using Vector->Geoprocessing Tools->Clip I only get an empty shapefile as an ...
1
vote
1answer
297 views

How to go with…somewhat complex geological maps in QGIS?

Just a follow-up to this question QGIS: Line to polygon conversion. Not sure do i have to continue there itself... We are currently digitizing a geological map...which has 36 features in total. Some ...
1
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1answer
88 views

QGIS: Line to polygon conversion

Currently we are working in a geological project..in which all the Contacts, Linear & some other geological features have to be captured. The thing is most of the features have to be Captured as ...
1
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1answer
54 views

Eliminate 0 Values From Raster

Arcgis 10.2 I currently have a raster file that I want to turn into a set of polygons. This will help me to create specific buffers around certain points. The extent of my values are 0, and 1. When I ...
3
votes
2answers
122 views

Can I convert the sharp edges of a polygon easily to round edges?

I use the python module "shapely" to make Polygons (like below). Can I convert the sharp edges of a polygon easily to round edges? Such that when I have unified some polygons I could issue a command ...
1
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2answers
119 views

How to select island polygons witin the same polygon layer?

i have a dataset containing many polygons. In this dataset some polygons have other polygons (as a donut) inside of them. So those island polgons are contained by only one polygon but it originated ...
1
vote
1answer
197 views

How to perform a true GIS clip of polygons layer using a polygon layer in R?

I would like to do a true GIS Clip in R of soils polygons using a series of single boundary polygons, but I cannot find an R function to properly do it. It should work just like the CLIP function in ...
0
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2answers
85 views

merging shapefiles . an error occured during the merge operation

i am trying to merge multiple polygons of a feature. i select them via select features by polygon and use the advanced digitalizing toolbar " merge selected features" option. it worked for some but ...
3
votes
1answer
56 views

Extra detailed bounding polygon from many geometric points

I have a database of around 100,000 postcodes each with lat/lon which I have converted to geom type in PostGIS. Each postcode also has one of 5 "regions". I wish to generate an accurate bounding ...
2
votes
3answers
207 views

Merge 30000 polygon shapefiiles in a logical manner in ArcGIS model Builder

I have 30000 shapefiles (a1.shp to a30000.shp). They are all polygons. Each polygons has one and only one polygon feature in it. I need to Merge the polygons into 1000 shapefiles. My output would be ...
1
vote
2answers
182 views

How can I group Points to make polygon via Python

I have an array of coordinates Point= [lat,long] ListPoint= [[38.203655,-76.113281],[38.10,-76.12],..] I wanna make a polygon that contains all these points ? There is a project developed by ...
1
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0answers
114 views

How do I smooth edges of polygons in QGIS?

Is there a built in function or plugin I can use to achieve smooth lines for my polygons instead of the blocky ones I have now?
0
votes
1answer
52 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
0
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2answers
58 views

How to export a shape polygon to a file

Is it possible to to export a shape polygon to a file? I want to export the polygons from a country to use them on a different map system,
0
votes
1answer
66 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 ...
3
votes
1answer
109 views

How to give elevation information to a polygon feature class using existing TIN file ? (geological mapping)

I'm an ArcGIS 10.1 user. My issue: I have a printed form of a map which depicts geological bodies being surface rock occurence. Additionaly, there are elevation contour lines. I digitized the map by ...
0
votes
1answer
147 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 ...
1
vote
0answers
43 views

Entity handle from Visio

I have successfully imported the polygons from a Visio diagram via dxf into QGIS by using the "space" shape in Visio (a normal rectangular shape comes through as polylines, not as a polygon). Very ...
2
votes
1answer
134 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 ...
5
votes
3answers
219 views

adjusting polygons to boundary and filling holes

here's the problem: Where: 1: department boundary 3: polygons inside department boundary that "touch" the department boundary(1). They are not necesary fitting well inside 2: holes between 1 and ...
1
vote
1answer
73 views

Calculating distance between borders when one polygon inside another polygon?

I am brand new to ArcGIS and having some trouble. I would like to calculate the distances between the border of one polygon to another polygon. However, these polygons overlap. Thus when I use the ...
4
votes
2answers
177 views

Converting shapefile to raster: Character attributes

I've got a shapefile that I would like to convert into a raster, but the trick is that the attribute I want a raster version of is character data. I'm familiar with geoprocessing using GDAL (in the ...
0
votes
2answers
82 views

How to select and shade polygons I am interested based on existing shape file in Arcgis 10.2

The shape file already includes polygons I am interested and others. I want to make a map put in my paper showing which regions in the world I am interested. Thanks.
2
votes
1answer
47 views

How to dissolve geodatabase map across two subdivision levels in Arcgis 10.2

The existing polygon database contains attribute table with the following structure, and has three levels; country, state, and city (and many other countries not listed below). I want to dissolve the ...
0
votes
1answer
167 views

How to generate random GeoJSON polygons (latitude, longitude)

I am looking how to generate polygons in GeoJSON format with random locations (latitude, longitude), if I generate totally random set of points it will not produce valid polygons. So my question is ...
4
votes
3answers
137 views

How to shrink polygon on two sides?

I have a polygon which I know is a rectangle, although it may be at any orientation: I want to shrink this polygon by a third of the width from two sides, so that I just get the strip in the middle ...
0
votes
1answer
54 views

CartoDB simple process

I'm attempting to create a simple process with CartoDB, I have a layer with number of polygons, I want to to run a SQL with a multipoint line to report which polygons were intersected.
0
votes
1answer
166 views

Looking for a simple hatching algorithm

If I have an arbitrary polygon, and wish to hatch it with lines at a given angle and spacing, is there a simple low-level algorithm which will return the set of hatch lines inside the polygon?
2
votes
2answers
210 views

Simplify Multigeometry polygons in QGIS

I am really new to QGIS and KML so this might be obvious but I am too ignorant to know what to do. I have some KML files I would like to use in an application but they are much more complicated than ...
2
votes
2answers
455 views

How to convert a shapefile to a grid file

I was wondering whether anyone might be able to tell me in layman's terms how to convert a polygon layer to a Grid file in ArcGIS 10.1 or ArcGIS 10.2?
0
votes
0answers
45 views

save polygon from image to PostGIS database

I'm working on a software to detect buildings from satellite imagery. so far I have managed to separate the building with other objects of the image. My problem now is how to save every building in ...
0
votes
0answers
35 views

QGis Filtering postgis layer with boundbox

I know It is possible to split a polygon feature by interactively drawing a line over it in QGIS 2.0 with the Split Feature command.The issue i have is that postgis layer i am trying to work on is ...
3
votes
1answer
167 views

PostGIS - when I add a polygon, delete overlapping areas in other layers

I'm starting to work with PostGIS and I'd like to solve the following problem: In my database, I have multiple land use class layers, for example: "residential", "industrial", "commercial". The ...
0
votes
0answers
46 views

Why does it take so long to run zonal statistics?

QGIS 2.0 Windows 7 I have pulled agricultural data from NASS CDL in tiff format. I want to track where a certain crop has grown over the years. My intention was to use a county shapefile overlaid ...
2
votes
1answer
108 views

Area of polygon split by a line

I need a query that return the area of two polygons that have been split by a line. This is what I did so far: SELECT ST_Area(ST_Split(surface.geom, limite_a.geom)) from surface, limite_a where ...
0
votes
0answers
41 views

Splitting polygon layer and joining attributes

I have two shape layers -- one a layer of counties in Florida and another a layer of MSAs in Florida. I would like to generate a new layer that has the following properties: MSAs that overlap more ...
0
votes
1answer
97 views

Numbering rows and columns in polygon grid (fishnet)

I seem to be a bit stuck on what i thought would be quite straightforward. I've created a fishnet of polygons, all 25 x 25 metres, 100 polygons by 100 polygons. My main task is to create a ...
2
votes
1answer
283 views

How can I filling ring in QGIS 2.2?

I created a polygon which covers a park. But I want to distinguish some small buildings located inside the park. Consequently, I want to distinguish them and use them as independent patches inside the ...
2
votes
1answer
162 views

Calculate the number of points in a freehand polygon ArcGis Javascript API

I'm drawing a free hand polygon on my map. Now I want to calculate the number of points found in that polygon. I have done this code, which my now is giving me the number of points found in the map ...
2
votes
3answers
291 views

Combining different geometry types into same feature class?

I've searched the question in this blog. Maybe I don't use the right words but anyway my problem is not present in any post so I'll try to explain my question by opening a new one. I have a polygon ...
1
vote
1answer
87 views

How do I add coordinates to a polygon layer to be able to sort the polygons from north to south in QGIS?

I have a polygon file, where each polygon represents one property. I want to be able to sort the polygons from north to south or vice versa. I need them to be sorted in this way when I export them to ...
0
votes
1answer
49 views

Query to create polygone from lines that touches in POSTGIS

I am trying to create polygons from a line layer with a spatial query in postgis the probleme is i dont have a lot of information on the lines only id of each line and geometry thanks for your help
2
votes
1answer
148 views

Batch create fishnet using FME

I want to create a fishnet based on the extent of individual polygons from a list of polygons. I plan on processing each resulting fishnets further. I am maintaining a worldwide data set on Quarter ...
1
vote
2answers
391 views

QGIS Valmiera, Labels only show for part of polygons

Using 2.2.0-Valmiera on Ubuntu 13.10 I have for Croatia 21 Counties as polygons. Labels show only for 12 counties: here I see that no labels are shown for multipart features. So I checked "Show ...
0
votes
1answer
49 views

Get all points with in some range of a point (or range of point)

I have got a list of points and a fixed range (10m). So what I have to do is for each point I have to find all the points present in a table with the 10m range of the given point. For example: Let ...