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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13 views

Problem creating polygon in a layer

I am working in c++ qt4.8.5 and api qgis 2.8.2 c++. In my application I had to put polygon to define attractive zone. I found a great post in stackexchange (86812). I have based my on this post and on ...
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1answer
14 views

Polygon overlap into new layer on CartoDB

New cartodb & PostgreSQL user here. I have two rows in cartodb table and each row has its own polygon. The two polygons have some overlapping area. How can I create a new polygon of just the ...
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0answers
15 views

Handling features as events [on hold]

I have a question related to handling features dynamically. In the two desktop GIS systems QGIS and ArcGIS we can import CSV files or database tables as XY events. These can be handled as dynamic ...
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0answers
31 views

Polygons within Polygons Spatial Analysis

I have a polygon layer of planning applications and I am wondering if anyone can give any advice and or has seen or written a blog post that might point me in the direction of creating relationships ...
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0answers
11 views

Creating regions (set of lat, lng) on map using other than ArcMap?

I'm writing a project for school and as a part of the project I need to tell if a certain point is within a given region (which is a polygon made of lat, lng tuples). So far I was working with ...
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0answers
29 views

How to recognise building type from polygons?

I have a number of building polygons which are extracted from the aerial images, along with their postal address. (The aerial images are not available in my case.) For example, the polygon of a square ...
4
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2answers
39 views

How to export a polygon based on elevations using a DTM or a DEM

I have a LiDAR generated DTM and a DEM (accurate to 10x10 feet). I am trying to export a polygon within a boundary which includes all elevations below a specific number. Seems like this should be ...
1
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2answers
60 views

Fix Polygons to be true Rectangles

I got a featureclass polygon of 4 point polygons that delineate the coverage area of a georeferenced image; these polygons will later be map sheets. Anyway I discovered some of them are not true ...
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1answer
32 views

Error in saving polygon with openlayers-3 and geoserver 2.7?

I'm using OpenLayers 3.8.2. I have wfs layer. I insert a feature. I save this feature as follow(I use geoserver 2.7-SNAPSHOT in server side): var features = source.getFeatures(); var insertedArr = ...
2
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1answer
21 views

Constructing a simple zip code polygon map in CartoDB

I'm new to using CartoDB. I suspect that what I want to do is rather simple but I would love some guidance. I want to produce a map that depicts multiple layers, the first of which is simple zip code ...
1
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1answer
33 views

How to calculate overlap area of two polygons?

I am a beginner in the world of GIS. I have one table polygons with each polygon having north-east and south-west coordinates. And for every polygon, I need to find area of overlap with other ...
1
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1answer
18 views

Trying to create colour co-ordinated values on a map from data from a csv. file

I have a list of values for some data recorded via Magnetic susceptibility, I have these in a shapefile and want to try creating a colour map out of the values. The values that I'm using relate to, ...
1
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0answers
18 views

Toggling selected feature when using Node Tool of QGIS?

Does anyone know of a way, when using the Node tool in QGIS to edit a polygon, to choose or toggle which feature (within the same layer) is being selected if they share a boundary? It seems to just ...
0
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0answers
22 views

How to properly draw and label overlapping polygons?

I would like to show overlapping polygons on a single layer. The polygons are coloured based on a property and labelled according to another property. The problem is then twofold: The polygons are ...
4
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2answers
84 views

Polygon points to Polyline

I am trying to create a polyline from the points that I query from a polygon. I have a polygon, and I am getting its edges, casting them to segments, and then use QueryNormal to get the mid point ...
0
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0answers
18 views

Modifying attributes of a shapefile using java

I have a polygon vector shape-file in which each feature has an integer attribute. I want to update this integer attribute(for all features) programatically using java on regular intervals of time. ...
0
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1answer
46 views

Splitting all polygon features in a shapefile into smaller equal width polygons

I have a shapefile of thousands of polygon features, that i would like to break up into smaller pieces (i.e. break a square into 8 equal pieces). I have read all over these boards for the right ...
2
votes
1answer
32 views

Reclassifying a polygon using field calculator

I am trying to reclassify a polygon into three classes: 1 and 2 = 5 3 and 4 = 3 5 = 1 I have been trying to do this by calculating a new field in the attribute table but I am very ...
2
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1answer
16 views

Leaflet polygon (multi polygon) to CQL equivelent

I am using leaflet with geoserver. I want to set up a CQL filter to do an intersect but having an issue with getting the geometry from leaflet polygon to cql polygon. For instance, the feature has ...
2
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0answers
25 views

Prevent polygon feature (catchment) overlap for land-use extraction using QGIS?

My aim is to calculate catchments for around 150 points and to extract land-use variables for them. In order to do so I need a vector dataset where no polygons overlap. This, however, seems to be a ...
1
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2answers
28 views

Geographical Field Points of a Boundary

I gathered field points with a TOPCON hand held receiver. I saved the points as a shape file and brought them into arc map. I used the editor tool to connect the points and created a polygon. Is ...
1
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2answers
41 views

How can I move a set of polygons in ArcGIS Pro?

I am very new to mapping and I have loaded a set polygons from a shapefile into ArcGIS Pro. They appear correctly however they have clearly lost (or didn't have in the first place), their longitudinal ...
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0answers
16 views

Layering polygons over neighborhoods?

I would like to layer a polygon with 30% opacity using different colors over OpenStreetMaps or Google Maps like so: How might I go about doing that?
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1answer
38 views

want to make all poygons have z values as 0

I have polygons which stores different z values as vertices in Arcgis. I want that all z values must be equal to zero. How can I make this possible??
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0answers
32 views

How to show two layers at the same time in Qgis

I have a question about Qgis layers. I want to see two layers at the same times. one is lines which are boundary lines and the other is polygon which are district. when i was surfing about this ...
2
votes
1answer
33 views

How to calculate the form (or shape) factor of a polygon?

I am using QGIS to calculate the form (or shape) factor of polygons following what Louf and Barthelemy did here: http://rsif.royalsocietypublishing.org/content/11/101/20140924 The form factor is ...
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2answers
42 views

How to Dissolve Polygons Inside a Feature Class Based on Attribute Conditions

I have a large shapefile (saleArea.shp) which includes hundreds of small adjacent polygons. I would like to dissolve the polygons based on some conditions from tValues field into 5 bigger groups like ...
1
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1answer
31 views

Extracting the closest Point to a Line within a Polygon using ArcGIS for Desktop

I have the following shapefiles: Polyline: Detailing a road network. Polygon: Containing approx. 2000 polygons enclosing sections of that road network. Point: Containing numerous (OS Addressbase) ...
0
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1answer
17 views

Intersection of two vector tables data in postgresql

I have satellite raster data is converted in to pixels using create table gtru_tile_pix as SELECT (ST_PixelAsPolygons(rast)).val, (ST_PixelAsPolygons(rast)).geom FROM ...
4
votes
1answer
34 views

Identifying a cluster of polygons based on attributes

I'm trying to identify a cluster of contiguous parcels that, when combined, add up to at least a given size and, when combined, have an assessed property value less than a given $ amount. I have a ...
0
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0answers
21 views

Changing Polygon shape on Zoom in and Zoom out in google maps using javascript

In my application iam using google maps v3, on page load with default zoom level of 15 i load few polygons by passing points(latlng coordinates) from database on the google map now my question is when ...
4
votes
1answer
93 views

Creating shapefiles using textfiles in QGIS

I have a shapefile in QGIS which has polygons in it . There are several other attributes for each feature . I want to add another attribute to each feature . The value for this attribute is available ...
0
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3answers
49 views

Is there any web-gl js libraries for creating 3D bar overlap city map? [closed]

Is there any some web-gl js libraries for creating 3D bar overlap city map? More details: http://ny.curbed.com/archives/2015/01/09/3d_map_shows_where_nyc_housing_is_priciest_cheapest.php ...
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0answers
13 views

How to load points in a SQL server polygon table?

I have a spatial table in SQL server which stores both points and polygons geometry and I am using the table to return geoJSON for API calls. I want to load some points to this table with shapetype ...
2
votes
1answer
32 views

Convert Postgresql Polygon to PostGIS POLYGON

I have an existing table in postgres which contains a plain old posgresql polygon. I have added a new column using SELECT AddGeometryColumn ('public','fences','geom',4326,'POLYGON',2); I would ...
1
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0answers
22 views

Collect near polygons [closed]

I have the following data: The data have 5 level (in tones blue). I want to collect only the nearest polygons with the same level and sum the number (represent client number). When I collect only ...
1
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1answer
52 views

Performance Improvement of Postgres vs PostGIS

I am trying to run the following query thousands of times per second to determine which is any polygon contains the passed in point. SELECT * from areas WHERE poly @> ? Poly is the name of the ...
0
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0answers
22 views

Intersecting polygons to a focal polygon with the same cell ID and also obtaining the length of the joining edge

I have a series of polygons, where there is a focal polygon (a type of coral reef). The other polygons are cut to the centroid of a cell where the focal polygon is included. The cell ID is given by ...
0
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0answers
12 views

how to use st_intersection() with re-projection in POSTGIS?

This is a shipping route from 'portland to busan' and I want to check the route against land_polygons like how much distance is traveled by a route through land.And the problem is while checking the ...
0
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1answer
35 views

Multipolygon From Multilinestring PostGis

I have been looking for a answer for days. I dont even know if its possible. Tried: ST_AsGeoJson(ST_MakePolygon(ST_transform(geom,4326))) ERROR: Shell is not a line ...
0
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2answers
35 views

PostGIS Multipolygon - holes

I have MULTIPOLYGON in my PostGIS database to store countries (with islands etc.). But I need to add holes to my borders for lakes. How can I store multipolygon with holes? I am using ...
1
vote
1answer
33 views

How can I assign an object in a shapefile to a location based on another shapefile?

I have two different shapefiles to work with: one of them has polygons representing tree canopy data and the other is a shapefile for census tracts in the area I am working on. I am trying to figure ...
0
votes
1answer
53 views

Clip lines by overlapping polygons

I want to cut a line shape into parts by polygon areas. No problem so far. But the polygons overlaps each other at the border. I need one line result for the whole area of every polygon. Any ideas for ...
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0answers
13 views

Donot Polygon in QGIS [duplicate]

When I am creating a polygon inside of another polygon, both the polygons are selected, Please help me to create donot polygon in QGIS.
1
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0answers
26 views

QGIS split line into segments on polygon

Is it possible in QGIS to split a line into segments given which polygon it falls within? I am using 2.8. For example, a line that passes through three polygons will become three separate lines. Each ...
1
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1answer
38 views

Difference between intersect {raster} and gIntersection {rgeos} in polygons - R?

I am interested in knowing the difference between tools: intersect {raster} and gIntersection {rgeos}** tools in R. I have several overlapping polygons and I am interested in their overlap, but mostly ...
3
votes
2answers
73 views

What percentage of polygon x is in raster pixel y, efficiently

I feel this is a competition worthy problem, due to its size. I would like to weight a set of raster pixels to the attributes of a set of polygons. To do this I need to know the proportion of each ...
1
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0answers
23 views

Enable editing only one feature in a Polygon Layer using PyQGIS

I was thinking of locking neighboring polygons (parcels) by disabling editing on them, while editing would be possible on the polygon at the center. This means other polygons can also be edited in ...
0
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0answers
10 views

Divide/Split single polygons from one Shapefile using ArcGIS for Desktop? [duplicate]

I have a map of Austria which shows all the federal states in own polygons. As a whole - sure - you get Austria. I know how to make several states invisible so that you can just see particular states ...
0
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2answers
18 views

Java library for polygons interesection

I have an Android app when I have multiple polygons of a person's position, and I want the intersection of these polygon to know his exact position.