The process of connecting two or more datasets based on a common attribute or spatial location.

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22
votes
4answers
13k views

Joining non-spatial CSV file to spatial data (shapefile) using QGIS?

I have a CSV file which has postcode data in a field, but it is non-spatial e.g. no Easting and Northing. I have a shapefile with postcode in a field and some additional data. I want to join the ...
18
votes
4answers
7k views

How to join attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
13
votes
1answer
2k views

Why do simple joins on small datasets slow down ArcMap so badly?

ArcGIS 9.3.1, ArcInfo. I have some small file geodatabase and SDE featureclasses (few thousand records each, 50 columns) that I am doing attribute joins on. After the joins, drawing of the map is ...
12
votes
2answers
11k views

How to join external tables with a shapefile's attribute table in QGIS?

I need to join a .csv table into an attribute table of a shapefile. I wanted to do this with QGIS and i don't seem to find anyway of doing it. I know that the mmqgis plugin does it, but my shapefile ...
9
votes
5answers
13k views

How to join multiple records to single feature?

apologies for what I'm guessing is a really easy problem to solve. GIS user, not programmer here. I'm trying to create a join/relate in QGIS where I have a shapefile of buildings and to that I would ...
9
votes
2answers
2k views

After joining shapefile with CSV file graduated symbols option unavailable in QGIS?

I have successfully joined data from a csv file to a shapefile in QGIS but for some reason I am having trouble symbolizing my data. I want to use a graduated symbology however this option is not ...
9
votes
1answer
2k views

How to perform a spatial join of point and polygon layers in PostGIS?

I have a point dataset representing households that I want to associate with a parcel layer (i.e. assign its parcel_id). With ArcMap, I could spatially join the polygons to the points and specify that ...
8
votes
2answers
3k views

Join attributes of point and line layer by location (closest distance) in QGIS

My problem is the following: i have a line shp (target layer) and a point shp (join layer). the second one (point layer) holds an attribute which i want to join with a line layer based on closest ...
8
votes
1answer
186 views

Can you use wildcards for column headers in Field Calculator?

I know you can use wildcards for fields like so (in the Field Calculator): case when "column" ILIKE '%example%' then 1 else 0 end Can you do something similar for the column headers themselves? I ...
7
votes
2answers
2k views

Difference between two layers in PostGIS

What is the right way to calculate the difference between two layers? I tried to use the following approach: SELECT ST_Difference(river.geom, lakes.geom) FROM river LEFT JOIN lakes ON ...
7
votes
1answer
7k views

Joining polygons in R

I am wondering how to join spatial polygons using R code? I'm working with census data where certain areas change over time and I wish to join the polygons and the corresponding data and simply ...
7
votes
3answers
5k views

Joining tables without losing original field names in ArcGIS for Desktop?

I'm wondering if there is any method to preserve the original field names in ArcGIS when I join csv. tables to a Shapefile. I ask, because sometimes I join tables with 10, 20 or even more columns ...
7
votes
7answers
34k views

Having problems with joining an excel table to a shapefile in ArcMap

I have a shapefile of lower layer super output areas (LSOA) for England and Wales and I have a spreadsheet of the indices of deprivation for each of the LSOA's in England. I want to join the ...
7
votes
1answer
5k views

Creating a spatial “Many to one” join

I'm trying to create what I call a "many to one" join. I don't know if that would be the correct term or not. I have a table that has unique account numbers for mobile homes (i.e. - M1007970) per ...
7
votes
4answers
4k views

How to close multipart polyline gaps in ArcMap

I have a multiple multipart contour lines that originally came from CAD drawing. I converted these into a polyline shapefile in ArcGIS. The issue I have is with gap in each contour lines that are ...
7
votes
5answers
860 views

How to programatically identify the “Joined Field” in ArcMap?

Is it possible to programmatically identify the Join Field that is being used to Table Join two datasets together in ArcMap? I am currently using ArcGIS 10.0, SP5 and would prefer an ArcPy solution, ...
6
votes
3answers
7k views

Creating join based on multiple fields using ArcGIS Desktop?

I have two feature classes in a File Geodatabase that I would like to join based on multiple fields. I've searched this site and Google and all I have come up with was to use the Make Query Table ...
6
votes
1answer
96 views

Is there maximum number of .DBFs that can be joined using ModelBuilder?

Is there a maximum number of .DBFs that can be joined using the Join Tool in ModelBuilder? I tried joining 480 .DBFs but results generated only 250 fields in the input table. Is this a glitch? I am ...
6
votes
6answers
1k views

How do I remove a join (between a standalone table and a feature layer) with ArcObjects?

I already know how to do a table join with ArcObjects, via the IDisplayTable, IMemoryRelationshipClassFactory etc. interfaces. Here are some links to resources that have example code for this: ...
6
votes
2answers
542 views

How to symbolize features with NULL values in graduated symbology?

I have a polygon feature dataset, and an attribute from a different table that I join (one-to-one) within QGIS in order to symbolise the attributes as a choropleth map. However, not all polygon fields ...
6
votes
2answers
1k views

Creating polygons from one to many relationship of points using QGIS or PostGIS?

I have a set of polygons that are in a one to many relationship with points. The polygons are administrative boundaries and the points have information on companies and percentage of ownership . I ...
6
votes
2answers
318 views

How to enumerate join values with ArcGIS?

I have two shape files (e.g. postal code areas and cities) which I want to join based on an id that both shape files have in common (the id would be the city name in this example). Joining the two ...
6
votes
1answer
1k views

Can Spatial Joins be used to perform One-to-Many Closest joins?

My situation appears rather simple, but it has given me headaches more than once already. I have a set of points and a set of polylines. I would like to use a spatial join to join the attributes of ...
6
votes
1answer
3k views

Spatial distance join between polygon and points using R?

I'm figuring out how to do a Intersection (Spatial Join) between point and polygons from shapefiles. My idea is to get the closest points and those points that match completely inside the polygons. In ...
6
votes
1answer
118 views

Joining Google Docs table to feature class at ArcGIS Online to use in Operations Dashboard?

I am using ArcGIS operation Dashboard. I get the Data Source from excel file that i have published using google docs as a dynamically data source. I need to join the excel table to hosted feature ...
5
votes
3answers
3k views

FME: Join attributes in text file with attributes in SHAPE file

I have a SHAPE file with points and different attributes - one attribute MyID. I also have a plain text file with several attributes - each in a separated column: MyID MyValue 1 A 2 B 3 C ...
5
votes
2answers
91 views

How to join a table to a shapefile with non-matching IDs and names (similar strings)?

I'm having an annoying problem that I'm trying to find an automated solution for. The shorthand version is that I have a shapefile and a table of created data for regions within countries. The created ...
5
votes
1answer
841 views

How to use a search cursor on a joined table in ArcMap?

I'm struggling to get a search cursor to work on a joined table view. I've used search cursors before, but never on data that has been joined. Arcpy keeps saying that some of my joined fields don't ...
5
votes
5answers
2k views

Spatial Join on two point featureclasses produces empty output featureclass

I have two point featureclasses that intersect each other. They are in the same projection and dataframe. The issue is, when I perform a Spatial Join the output point featureclass is empty. The file ...
5
votes
1answer
213 views

QGIS 2.2 - possible to do a JOINS from the Action list?

I have a set of layers that need to be joined (Layer Properties > Joins) to one specific layer. The reason for this is that I will be updating and adding new layers into my project and would like a ...
5
votes
1answer
394 views

How do “join field” and “target field” work?

New user. This should be simple, but I can't figure out how to perform this basic join in QGIS. (It works in Cartographica.) My shapefile (IL_BNDY_County_Py) has two fields/columns in its attribute ...
5
votes
1answer
58 views

Is it possible to have a 1:n join which takes the min, max, or average value?

I need to join the attributes of a shapefile with the one contained in a .dbf (or .txt) file. I currently use the "join" in the properties menu, but I have a problem. In the shapefile I have one ...
5
votes
1answer
249 views

Reading an Existing Join

Confused again. I was finally able to run ArcCatalog and create a join in my map document (I will do the deed programmatically eventually) but I was interested in how a join looked once it was ...
5
votes
1answer
504 views

How do I avoid text field truncation when saving a table join?

Using QGIS I've joined tabular text data (all in fields of less than 255 characters) to a shapefile via a CSV file. All looks good in the joined table but when I save to a new shapefile to make the ...
5
votes
1answer
742 views

How to merge linestrings that don't touch based on common name?

I had a table of road line strings that contained duplicate road names with different geoms for different line segments. I extracted the duplicates to another table. I now want to join these segments ...
5
votes
3answers
985 views

SDE views not showing values in joined table

I created an SDE view between a point feature class and a table (stored in SDE) - the join is done on a text field called RFRNC. I changed the view so that it is now a LEFT OUTER JOIN in line with ...
4
votes
2answers
1k views

Join a CSV file to shapefile using gdal/ogr?

I have a shapefile with several attributes, for example YEAR, COUNTY, and AREA. I also have a CSV file with more fields that I want in the shapefile, such as POPULATION. Both the shapefile and the CSV ...
4
votes
2answers
1k views

Spatial join - many to one

I'm trying to do a spatial join that takes the attributes of multiple polygons and applies them to a single polygon in another layer. The data is currently in a geodatabase, but can be exported to shp ...
4
votes
3answers
2k views

Copy dbf data into a shapefile in Arcpy

Basically it's to perform a one-to-many join in a python script, from a dbf to a shapefile. I saw (Greg Krakow's method) using QGIS, but I can't use it (I'm working on it, but QGIS is not yet ...
4
votes
1answer
2k views

How to Calculate Field in joined table using ArcPy?

I have to calculate a field based on another field in a joined table, but an error occurs: "Parameters are not valid. ERROR 000728: Field !Table_A.field_A! does not exist within table" My code: ...
4
votes
1answer
941 views

Most efficient method to join multiple fields in ArcGIS

I have as set of shapefiles with approximately 300000 polygons each, as well as corresponding point shapefiles and tables with approximately the same number of row (equal or less rows than the ...
4
votes
2answers
2k views

keep the same field headers after joining a table to a shape file in QGIS

I noticed that after joining a table to a shape file the headers of each fields in the table used for the join are changed by QGIS and they are attributed to a different name. For instance, i had a ...
4
votes
2answers
84 views

One-to-many joins on a feature class to a table

I am using ArcMap 10.2.2 with an Advanced license. I have used ArcMap for other basic analyses, but am fairly new to the program and have only basic coding skills, with no SQL experience outside of ...
4
votes
1answer
794 views

ArcObjects joins and non-persistent fields after joining to multiple tables

I have inherited a truly awful and very large ArcObjects project that was originally written in VB and then ported to C#. Apparently the source code I have been given is not the latest version and I ...
4
votes
1answer
680 views

Spatial Join in PostGIS according to Line Attribute

I am in the process of building a data warehouse in PostGIS, that will store the length of the road network of a country (Lines) per Administrative Area (i.e. Province or State, referred to as AA ...
4
votes
1answer
60 views

How to automate joining SQL Server non-spatial database tables to ArcGIS shapefile

I have dozens of SQL Server non-spatial database tables. These are common tables, the column types are: nvarchar, int and float. I try to use Arcpy to automate joining these database tables to ...
4
votes
1answer
94 views

Conditional Spatial Join?

I need to join two layers (a fishnet grid and land cover). I'd like the join to occur only if the the land cover occupies 50% or more of each fishnet grid (See image below). Can anybody provide an ...
4
votes
1answer
486 views

Find max and min values from a table based on two fields

I have a geodatabase table with the following fields: County_Name, State_Name, Date_Time, Customers Example Alameda, CA, 8/1/2014 12AM, 6 Alameda, CA, 8/1/2014 1AM, 1 Alameda, CA, 8/1/2014 2AM, ...
4
votes
3answers
2k views

How to join two tables using date, time, lat and lon as common field?

I am sorry if the question is elementary but I did not find any clear discussion or guide to understand how to run a query in postgresql. So that a pointer to another website would be also useful. ...
4
votes
1answer
177 views

QGIS 2.0.1 linking table issue, MSSQL 2008 database

I'm trying to link tables in QGIS 2.0.1 and MSSQL 2008 database. I can link them but when I try to open the attribute table QGIS throws an error and shuts down creating a *.dmp file. I saw that ...