All Questions
152 questions
2
votes
2
answers
85
views
Update 1 random value in a group of values
I have an attribute table with a date field and a random field. The date field has three different times for each day. I need to input a '1' in the random field for one of those three times in each ...
- 85
0
votes
1
answer
339
views
Filtering out clusters of features based on collective area threshold using QGIS/python?
I have a map I generated that roughly estimates timber industry land ownership (designated by the green on the map) in the counties surrounding the Salish Sea in the US state of Washington:
I want to ...
- 673
2
votes
0
answers
186
views
Grouping layers by attribute value and finding nearest neighbour using QGIS?
I am new to QGIS.
I have two layers (layer_a and layer_b) consisting of two sets of points.
If I want to find the nearest point in layer_b for each point in layer_a, I can just use the Distance ...
- 121
1
vote
1
answer
1k
views
Grouping database results based on intersection using MySQL GIS?
I am using MySQL GIS (5.7.18).
I have a number of locations in the database. I also have a number of other polygons (not in the database).
I would like to perform a single query, intersecting all ...
- 111
1
vote
0
answers
82
views
Using a postcode sector map with a population attribute, create clusters of those sectors to have a total population within a defined range
I have a postcode sector map in QGIS and one of the attributes is 'population'. I am trying to create a map showing what postcode sectors would need to be clustered together in order to split the ...
- 29
4
votes
2
answers
825
views
Mapping building to only one grid which contains 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 ...
- 43
2
votes
0
answers
730
views
Clustering points into *n* number of groups of equal counts with ArcGIS
I have to divide points into groups. These groups will be used by agents to talk to property owners. The goal is to make the agent's job easy by grouping parcels that are near each other together, as ...
- 349
1
vote
1
answer
2k
views
QGIS Group Points Together Based on Multiple Attributes
I'm using QGIS and I want to group points that are:
within 20m of each other (as I have multiple mobile basestations on the same site)
based on a categorical variable (the mobile operator)
I have ...
8
votes
1
answer
1k
views
Finding density centroids within polygons in PostGIS
I want to find the highest density of OpenStreetMap nodes within a dataset of census geometries. I want to tie the census data to the location of the node which is most central in terms of population. ...
- 2,299
1
vote
2
answers
99
views
Selecting features from grouped shapefile
I have downloaded some glacier outlines from the GLIMS database (http://www.glims.org/maps/glims) as a SHP file.
This contains multi-temporal data, that is, more than one outline per glacier (more ...
- 111
1
vote
2
answers
390
views
How to cluster/group points based on their frequency and event time without overlapping them?
I am trying to group around 100 points based on their frequency and occurred month (similar to https://i.sstatic.net/i7Mzi.png) but I haven't found a solution yet.
Tried many tools in QGIS but till ...
user108470
1
vote
1
answer
811
views
Clustering point data to obtain maximum count groups using QGIS?
I am working with a data set of over 3000 points which I need to cluster/group based on a distance criteria.
What I would like to do is build clusters from the point data which contain the maximum ...
- 919
2
votes
1
answer
381
views
Group geotagged photos in MapInfo
The situation is:
There are many photos (between 900 to 3000), geotagged and I can see them on MapInfo. The photos are of certain objects and there may be 2 to 8 photos for each object. These objects ...
- 509
3
votes
0
answers
215
views
Grouping neighbor points based on field sum in QGIS
I have about 14,000 points. These points have a specific field "time", an integer value, mainly between 1, 2 or 3.
I would like to split these 14,000 points into groups based on the "time" field ...
- 165
1
vote
2
answers
2k
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 ...
- 528
0
votes
0
answers
66
views
How to make analyzeGPS distanceGPS group by trip?
I have a dataset with id, lat, lon and time, where each trip has a unique id.
When I try to use mutate with the distanceGPS function in the AnalyzeGPS package and group by trip using this code:
gps%&...
- 11
5
votes
1
answer
1k
views
Dividing polyline layer in clusters with specific requirements in ArcGIS for Desktop?
For my work in ArcGIS 10.2 for Desktop I need to divide line layers into clusters/groups. Currently I am doing this manually, but I like to automate this. The line layers can consist of 50 up to 2500 ...
- 55
2
votes
4
answers
271
views
'Joining' polygons using PostGIS?
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 like ...
- 1,073
1
vote
1
answer
1k
views
Using FME to aggregate POI to one point
I want to aggregate points of interest (POI) using FME. The aggregation should make it possible to group all POI within an area based on a buffer distance from the centerpoint of n POI.
This would ...
- 3,201
7
votes
1
answer
467
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 ...
- 71
2
votes
0
answers
460
views
Problem with grouping items in print composer- QGIS 2.14
This is print composer:
when i group all elements with "group items" and minimize the frame- some items step out from the frame:
How can i group all items, and still maintain the same ratio of ...
- 4,082
3
votes
0
answers
1k
views
How to cluster point data into equal sized groups [closed]
I need to cluster point data into equal sized groups. I have 180 points and want to create 3 groups each containing 60 points. The groups should contain points which are close to each other. Is there ...
- 31
5
votes
2
answers
957
views
Grouping lines together to form one line after a distance threshold is met
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 ...
- 195
1
vote
1
answer
165
views
Grouping roads based on existing condition and AADT? (QGIS) [closed]
For QGIS software, I have municipality service agreement roads and an end-plan to group the roads based on close proximity (roads and communities close together or close to each other and on the same ...
- 11
2
votes
3
answers
255
views
Grouping and exporting a set number of features in ArcGIS
I have an areal feature class that has approximately 4,700 features. I need to divide this feature class into multiple feature classes that contain EXACTLY 60 features in each. Location of features ...
- 63
1
vote
0
answers
257
views
Use of Hot Spot Analysis (Getis-Ord Gi*) [duplicate]
I'm working with a polylines shape. I'm searching for a tool that could help me to define neighbourhoods using the values of the polylines.
I have good results with Hot Spot Analysis (Getis-Ord Gi*), ...
- 19
1
vote
1
answer
316
views
Combine / Group - ArcGIS attributes table [closed]
I need to group several rows in a single one, combining data cell (mainly “text”) in Arcgis desktop 10.2.2. One cell could have several records separated by comma. I have attached a screenshot in ...
0
votes
1
answer
994
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 (...
- 173
1
vote
1
answer
882
views
Group attribute tables values for use with conditionals - Python
I would like to group values in a field in an attribute table. The field contains duplicate values. These duplicate values should be grouped based on duplicate values, the field would look something ...
- 622
2
votes
1
answer
1k
views
Grouping points using grouping analysis to look at raster characteristics within overlapping buffers?
I want to extract averages from raster data that fall within buffer zones around a village point.
The problem is that the villages are pretty close together in some places and I need to come up with ...
- 163
1
vote
2
answers
52
views
Introduce year instead of whole date in date type field using ArcGIS Desktop?
I have a field with numbers in it (concentration of chemical compounds that were presented in aquatic environments) and I'd like to combine them with a field which would have date type capabilities ...
- 11
2
votes
1
answer
112
views
Identify groups of stacked geometries in PostGIS
I need to create a column in my PostGIS table with values identifying different groups of stacked/duplicate geometries, such that one group of stacked geometries might get a value of 1, another group ...
- 240
1
vote
1
answer
504
views
How to merge two point feature classes based on spatial location using ArcPy?
I have two point feature classes, each containing about fifty points.
These 2 point feature classes should be merged, or the points of feature class 2 added to feature class 1, as feature class 2 does ...
- 883
2
votes
1
answer
134
views
AcrMap- How to use the dissolve tool with large amounts of polygons?
I am a college student working on an independent research project and I am trying to figure out how many points fall within a polygon.
I am examining the impacts of zoning in the Great Barrier Reef ...
1
vote
1
answer
1k
views
Grouping points based of user-provided distance in ArcGIS for Desktop?
I have a point layer and I need to group/aggregate the points within a 1km proximity into 1 single point to create a new point layer.
I was trying to use Aggregate point and then Feature to point, ...
- 287
3
votes
1
answer
1k
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, ...) to ...
- 1,958
2
votes
3
answers
613
views
Dissolve without removing interior lines in ArcMap? [duplicate]
I'm fairly new to GIS and I'm having an issue that I hope someone can help me resolve?
Basically, what I'm trying to do is merge features based on a single attribute so that my table no longer ...
- 21
2
votes
1
answer
2k
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 ...
- 151
2
votes
0
answers
206
views
How to handle multiple rasters (precipitation data) in QGIS?
Currently I am working at a hydrological model for Rwanda which needs monthly precipitation data averaged over the area of subcatchments.
The precipitation data are 144 TIF's from CHIRPS for timespan ...
- 21
1
vote
0
answers
32
views
Grouping overlapping points by UTC Time, sum and average?
I have data from airplane calibrations where the plane flies in a crossing pattern; i.e. going E->W and W->E, then N->S and S->N.
I need to sum and average the values for both flights in each ...
- 379
1
vote
1
answer
78
views
Reducing the number of records
I have a very extensive GPS track from which I am trying to reduce the number of plotted points. I though that I would be able to do so by grouping by a round of the timestamp /900 ( every 15 mins ), ...
- 141
3
votes
1
answer
92
views
Get the full list of commons
In QGIS I've loaded the shapefile "province" in which attribute table contains 242 fields (the municipalities of this province) and also two other files downloaded from OpenStreetMap about hotels (...
- 259
2
votes
0
answers
193
views
Merge n number of adjacent polygons [closed]
I have over 17,000 individual polygons. I want to merge two adjacent polygons so that I finish with approximately 8,500 polygons. The polygons need to be merged based on location, merge two adjacent ...
- 37
0
votes
1
answer
80
views
Selecting inputs within groups - arcpy
I need help with some python in selecting correct input and near feature classes in Near Table analysis.
The project aim is to run Near Table Analysis (distance) on point locations collected at time ...
1
vote
1
answer
329
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 ...
- 115
7
votes
0
answers
323
views
Grouping carpool participant addresses for network [closed]
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 ...
- 3,185
2
votes
1
answer
365
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 heve ...
1
vote
0
answers
86
views
How to group different values of a variable so that they plot with same shape?
I have a table with two columns of number X and Y, and one column of strings called crystals.
crystals
A
A
B
C
B
D
B
C
Using ggplot2, how can I make a scatter plot of X versus Y with two ...
2
votes
0
answers
728
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 ...
- 121
2
votes
0
answers
88
views
Locating Multiple Points on Mutlipes routes by a Unique ID
I'm trying to get a "MEASURE" for Points along a route. I need ARCGIS10 Desktop Linear Referencing tools or other application to use a unique identifier to match the Lines in the route to points ...
- 49