Associating or clustering data based on common attributes or properties.

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2
votes
1answer
39 views

QGIS how to group by a category and sum multiple variables within that category?

I'm using QGIS for some analysis. I have data in this format: Name is a text variable and categories are all integers And I want to generate a sum for all categories for each name, ie a table like ...
2
votes
2answers
62 views

How to map a building to only one grid which contain more than half of its area using qgis?

I have a shapefile of a city map and I have created vector grid as polygons. After intersecting the two shapefiles, a building will map to all the grids it overlaps. However, if I just want it to ...
1
vote
2answers
63 views

Headings in legends

Is there a way, in the legend, to get the headings to stretch across multiple columns? For instance I have a layer with multiple attributes that are being displayed (in the example... fire hazard ...
0
votes
0answers
33 views

Handling Users and Permissions in Django Admin

Am developing an application where public will have to fill in a form (apply for service) and the applications received in ApplicationsAdmin.The applications are to be verified by a user from one ...
0
votes
0answers
43 views

Grouping Features by Proximity

I have a layer with 12,000 hotels across the US and I would like to put them into groups of 2 based on proximity. Each hotel would be in only one group with its nearest neighbor optimizing for the ...
0
votes
0answers
70 views

Cluster/Group based on distance and value field

I am using ArcGIS 10.2 basic level licence. What I am trying to achieve is to group a set of points based on a value field and to their nearest neighbour. My point file has a integer field and I ...
2
votes
1answer
118 views

GROUP BY on geography in postgres 9.4.0 returns wrong/different results

table definition: CREATE TABLE search ( id bigserial NOT NULL, location geography(Point,4326) NOT NULL, location_aggregated geography(Point,4326) NOT NULL, created timestamp with time zone ...
2
votes
1answer
306 views

postgis: cluster/group points based on distance

We have a set of thousands of points and want to group all of those which are within 100m distance from each other (to get the centroid from each group). A first idea was to build 100m buffers around ...
0
votes
1answer
79 views

Create certain number of Clusters, equal sum of Z value

Divide polygons into *n* number of groups of equal counts with ArcGIS 10.2 is very similar to my question. But instead of equal number of polygons, I have multiple points (schools) with a z value ...
2
votes
1answer
62 views

Difference between: join, merge and group

Suppose it is desired to make polygons A and B, and their respective attributes to be one unique polygon C. What is this GIS operation called? Is there any difference in GIS terminology about ...
0
votes
0answers
43 views

Reclassify weighted sum values

I have using weighted sum to find areas to plant trees. The values I get out by using weighted sum are 0.7-0.9 in floating point. I want to be able to reclassify this layer so I can then use region ...
4
votes
0answers
193 views

Grouping carpool participant addresses for network

I have a list of addresses of people participating in carpools to a workplace and a list of cars given by the workplace. Both lists change daily. I need to group people by their addresses and assign ...
2
votes
1answer
206 views

How would I group values in a field based on range of number using python, and then update the attribute table?

An example of what I'm trying to accomplish is described below, however they don't describe how to use the data update cursor to update the attribute column. data - Group values based on range of ...
0
votes
2answers
65 views

PostgreSQL/PostGIS - group by series of values

I need to sum up linear objects' length and to group them by intervals of several years. I have one table storing my objects like this : - gid serial NOT NULL, - year INTEGER, - the_geom ...
0
votes
0answers
63 views

Sort Proximity Results Into Groups Based on Distance from Center

The scenario is as follows: I have a database of pizza places with review averages. I want users to be able to find pizza places near a location and have them sorted by distance. Pretty straight ...
1
vote
1answer
143 views

How to do point-to-point near analysis conditional on common attributes of the two layers in Arcgis 10.2 (advanced)

I am measuring the closest straight distance from cities of interest (in a layer) to their capital cities (in another layer). Basically, distance between a city and a capital city is calculated if ...
3
votes
1answer
253 views

How to add an ID based on attributes in ArcMap 10.1

Given are: a polygon shapefile/feature class (FC) containing municipal districts a point shapefile/FC containing locations of, lets say, trees. My goal is to append an unique value (1, 2, 3, ...) ...
2
votes
4answers
145 views

Best way to 'join' polygons

I'm looking for the best ways to 'group' a budge of block polygons in a new polygon that should be the town. My block layer is something like this: Or zoomed: And I'm looking to get something ...
1
vote
1answer
95 views

Wrong output wth group by and aggregate function in spatialite

I have a grid and for every cell I want to set the column "landuse" according to the largest intersecting polygon. SELECT grid.PKUID, landuse.landuse, ...
15
votes
5answers
225 views

How to start a local GIS Users Group

My immediate geographic area is lacking an organized local GIS Users Group. I belong to a group that meets a couple times a year, but its about 1.5 hour drive. I'm thinking about starting up a Users ...
3
votes
3answers
2k views

How to group and count attribute data?

I have a problem with group same data to count it. for example, i want to group same code to one and count them. i can do it when i use MapInfo (Pic 1) but i can't in QGIS. (Pic 2: i can classify ...
2
votes
2answers
776 views

GROUP BY clause in the UpdateCursor arcpy.da

I need to specify a "group by" clause for UpdateCursor arcpy.da. From here I found out that it's possible to do using an optional pair of SQL prefix and postfix. But there are no examples and I'm ...
0
votes
0answers
146 views

How to draw polygons around known clusters

I need to split up an area into non-overlapping, but contiguous territories. I have n points on a map, which are partitioned into k sets. The partition is only partially geographic, meaning that ...
4
votes
2answers
4k views

group by timestamp interval 10 minutes postgresql

I need some help on this: I need to group by a period of time spliting up by 10 minutes: I have this query below that returns me a result set SELECT timestamp FROM table_1, ...
2
votes
1answer
328 views

Field calculation in ArcGIS Desktop?

i have a data which contain a code of area an value of area in shapefile, ex.: area|value 1|33 1|43 1|31 2|12 2|43 3|66 3|76 the question is how to calculate total value per area with arcgis, i ...
5
votes
0answers
464 views

Grouping analysis of points to divide a polygon into n number of sub-regions

I'm attempting to create n sub-regions from a polygon based on a cluster analysis of a bunch of overlapping raster layers (physical layers, eg: depth, currents, waves). Briefly, I can create a ...
5
votes
2answers
297 views

Grouping lines together to form one line after a distance threshold is met: ArcGIS 10

I have lines on a map showing the most direct way from point data to the coastline (polygon). I would like to group the lines if they are close to each other by a distance that I can set. Where the ...