# Tagged Questions

A geometric element defined by a pair of x,y coordinates.

115 views

### ValueError when instantiating LineString from a mix of tuples and Point objects

I'm new to Shapely, and tried instantiating a LineString object from a mix of tuples and Point objects like this: >>> LineString([Point(1,2),(2,3),Point(3,4),(5,5)]) I get the following ...
313 views

### WKT: What is the reasoning behind the concept of a POINT EMPTY?

In data formats like WKT and WKB, we have ways of representing "empty" geometries. That all pretty much makes sense: a "LINESTRING EMPTY" is a LINESTRING type with 0 vertices. Same with a MULTIPOINT, ...
121 views

### How to automate drawing a polyline from 2 intersecting datasets based on proximity?

I've been stuck on a situation recently where my company's data has to be integrated with another. Basically there are two point shapefiles comprising of >50000 points, and as shown in the image below,...
56 views

### Creating random location within a network from a given location and a given distance

For a habitat selection study, I am trying to identify availability. My species lives along waterbodies and I could assess distances moved between two consecutive locations using the network analyst (...
1k views

### The best way to convert points to polygons using ArcObjects

I have a set of points from GPS I want to convert them to polygons..I have two approaches to do this.1- convert points to polygon..I do this with below code: private IPolygon PolygonFromPoint(...
5k views

### Creating density map from point data?

I have point data, where one point represents one 1 storm water outfall, looks like this: (point data is across all of Long Island, New York). I am having a bit of difficulty finding the best tool ...
480 views

### How to compare two sets of points in QGIS?

I have two point layers with XYZ data; one set are points measured in the field and the second set is a Lidar data set. I want to check the accuracy of the Lidar in comparison to the measured data. ...
52 views

I'm currently developing an Android app where I need to show some information on a map, which is stored as Shapefiles (.shp + .shx + .dbf). I noticed that when the shapefile is opened in QGis, a nice ...
547 views

### TIN file to a POINT file

I have some bathymetry data in TIN format; I am able to open this in arcmap and view the terrain. However I need to use this data within a simulation framework called Delft3D, which needs the ...
349 views

### Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
182 views

### QGIS polygon centriods - How are they created?

I have been using QGIS to analyses spatial data and I created polygon centroids with the vector geometry tools. Now for a report I have to explain how these centroids were created. I have not been ...
195 views

### how to remove a point or polygon in shapely python

I want to place minimum number of sensors(circles) to cover a maximum area(polygon). I am using "Shapely",python module. I want to know if a sensor i.e a point buffer inside the range of the other ...
608 views

### Adding end nodes to a line

I'm hoping someone can help me here. I have a line feature and what I am trying to achieve is to determine is in which direction the line ends. I understand that this could be achieved with '...
1k views

### Iterating over all features in featureclass to intersect them individually with polygon using ArcPy?

I've got a point featureclass, and I'm trying to individually intersect each feature with a polygon featureclass to get some information about which polygon each feature is in. I did one intersect ...
441 views

### Intersection of two polyline geometries not returning expected coordinates?

T2B = arcpy.Array([arcpy.Point(1,2),arcpy.Point(-1, -2)]) L2R = arcpy.Array([arcpy.Point(0, 2), arcpy.Point(1, -2)]) L2R_line = arcpy.Polyline(L2R) T2B_line = arcpy.Polyline(T2B) cent = L2R_line....
235 views

### How to set a minimum point snap distance?

There are two points: A and B. I need to snap any points within a 65 m search radius (blue buffer) of point A. However, the snap distance of B needs to be exactly 5m apart from A (i.e. located ...
97 views

### Point to point and point to line [closed]

I have several points. These points are far from some lines. I want to make the following: If two points are closer to each other than the maximum distance of one of these points to the closest ...
122 views

### Can I create a cross section from points along a line without using a DEM in QGIS?

I have a set of points perpendicular to a river and would like to present a cross section of them. Like a simple graph in Excell for example, with Z as y axis and distance along the line as the x axis....
433 views

### Density analysis producing extreme values?

I have point data of gas flares and I am trying to create a simple density raster of those flares. Results are either 0 or in the 100,000-1,000,000 range (when there's 5 to 40 or so points in each box)...
216 views

### Buffers with Varying Distances around a Set of Points

I have set of points in one shapefile and I have a table with a unique identifier that matches each point. I want to make a buffer around each point, according to the radius that I have specified in ...
220 views

### converting random point order into polygons

We received a kml file with polygons but the points are not in a logical sequence and we end up with strange overlapping shapes that are supposed to be an open polygon. We did identify a point near ...
859 views

### How to calculate point from lat/long, angle, and distance? [duplicate]

I am trying to calculate the point from a given lat/long, a bearing, and a distance. This is for plotting weather given a aeronautical way point. For example: Given a waypoint with a known lat/...
740 views

### Calculating distances between points two feature datasets

I will do my best to explain my problem. I have two feature datasets. One set has about 100 points that are "city centers." The other dataset has points for each census tract in each of these 100 ...
526 views

### Export a large raster to a comma or tab delimited text file in ArcGIS 10.2 for Desktop

I have a large raster with multiple attributes in 200-meter cells, and I would like to export this to a tab or comma delimited file which contains the X,Y coordinates and all of the attributes. If ...
3k views

### How do you hide a feature within a point layer?

I know this is basic, but for the life of me I can not remember how to hide/disable a specific feature point within a point layer. This seems like it should be a 2-3 click solution, but working with ...
184 views

### Spike finder in PostGIS

I tried to modify spikeRemover from Schmidt & Krüger. My goal it's to obtain, for each polygon, the position of the spikes. I don't need to remove it. For some reason, that I can't figure out, my ...
983 views

### Change points to polygon

I have a map which has one data point per zip code. I would like to change those points to zip code polygons. Any ideas on how to go about it?
1k views

### Get points, along a polyline, at defined distance

I need to store into an array the points, along a polyline, at each defined distance. Example: A polyline length is 50m, I set the interval to 5m. I have to store in the array all the points along ...
47 views

### Extracting outtermost points from a irregular grid of points

Good day to all, I am using Arcmap 9.3, and would like to remove all points inside an irregularly placed grid, except the outermost (boundary) points. For example, I would like to keep the black dots,...
475 views

### Project point to map with Arcpy using GPS Coordinates

I am trying to create a new layer with just a single point using arcpy. All that is provided is a gps lat and long. It seems like it should be a simple problem but I just can't get it to work. I've ...
154 views

### GRASS GIS v.in.ply

I'm trying to import a .ply file from MeshLab 1.33 into GRASS GIS 7.0 using v.in.ply addon, but I get the error message: ERROR: List index must be integer, is uchar This appears to be referring to ...
252 views

I try to create a DB in postgreSQL with all the postal adress data for a specific country. Actually I have this table full of data: id integer NOT NULL DEFAULT nextval('plz_id_seq'::regclass), ...
1k views

### How to automatically draw lines with a given angle from one single point in qgis 1.8?

I'm new to qgis so please be patient. I need to draw a bundle of lines all originating from the same point and with a 10° angle between each line (e.g. lines bearing at 0,10,20 ..90..110..220..350). I ...
128 views

### Determining if polygon contains point to populate point's field with polygon's name using arcpy.da?

Am trying to check if the points in a point shapefile are contained within a polygon shapefile and if so, to populate a field in the point shapefile with the name of the polygon and to populate the ...
402 views

### Is there a “Disperse Markers” tool for QGIS?

I am using ArcGIS, but either I would like to use QGIS and maybe want to switch completely later. A have a point overlapping problem, as a result of geocoding of addresses. I have not found any ...
47 views

### How do i snap points to crossroads using ArcGIS 10.2?

I have some points (370 points) in a layer . These points must snap to crossroad layer . I could'nt find any tools in arcmap to snap points to crossroad layer. Is there any way to snap these points to ...
242 views

### PyQgis: How can I preserve order or index when adding features to a Vector Layer from a file?

As I read data from a text file and add points to a QgsVectorLayer (as well as related attributes), each new record gets 'stacked' on top of the previous one in the Attribute Table (and within the ...
83 views

I need to prepare a web service which will display the gradient of polygon points values. It has to look just like in this picture: link to the picture (please ignore the arrows). Each polygon is ...
201 views

### I have a table with a series of lat/long points - how do I convert them into polygons?

I have an Excel sheet with about 150 points (lat and long in decimal degrees) which belong to about 15 different polygons. The columns I have are FID, NAME (the same between polygons), POINTS (points ...
78 views

### How to show coincident point with different symbology in webgis?

our team have develop an webgis using ArcGIS silverlight API 3.1 .we have some points in database.These points are save in a table in sql server 2008R2 not in Geodatabase.The points have same ...
243 views

### Multiply point values by raster values

I have a point shapefile containing elevation values in the id field. The shapefile is overlaying a raster layer of the topographical slope. Is it possible to multiply the elevation value of each ...
380 views

### How to identify concentrated areas with multiple point values to produce a “heat map” appearance

I have roughly 1.6 million points statewide with values ranging from 1 - 4. I'm looking to identify concentrations of points based on their values (1,2,3,4). I know there are several different routes ...
166 views

### How to compare multiple spatial point patterns over a polygon

I have multiple point pattern distributions over the same region/polygon. Each point pattern distribution has different number of points. Here is an example of two spatial point patterns for the ...
448 views

### Produce line from components, length and angle

I have a CSV file, or point data file which includes information about line vectors which I have previously calculated. This file is outlined as such: x, y, dx, dy, length, angle(east_from_north) 1,1,...
274 views

### Generating points from chainage and offset

I have a polyline layer and an external csv containing road sign data. The csv has unique ID of the polyline, chainage along each unique segment and an offset. I have access to ArcGIS, MapInfo and ...
987 views

### Splitting polyline by points using ArcGIS 10.2 for Desktop?

I have a layer containing a curved polyline and I would like to split it at multiple point locations, which I have in another layer. In ArcGIS 10.2, I can do this with the tool "Split Line at Point". ...
856 views

### How to convert a point layer to a raster grid that shows the frequency of points per cell in QGIS

I have a point layer that shows the distribution of a species. Is it possible in QGIS to convert this point layer to a raster grid in which the value of each cell corresponds with the amount of points ...
64 views

### QGIS hides few graduated points after reopening project

I have a strange problem in QGIS 2.2 (problem is also present in QGIS 2.1). When I add a point (shapefile) layer, apply graduated style and change point size, everything looks fine. Then I save ...