GIS Stack Exchange
GIS Stack Exchange

Most Popular

more tags
1500 questions
34
votes
2 answers

Does QGIS have the equivalent of ArcGIS's Layer (*.LYR) file?

Using ArcMap, it is possible to add a dataset (eg a shapefile) to the map, and configure the layer's properties (such as the symbology, table joins, switching some attributes off in the Identify results, etc). This layer can then be saved as a Layer…
Stephen Lead
  • 21,119
  • 17
  • 113
  • 240
34
votes
10 answers

How do I develop my GIS programming skills?

I would like to develop my GIS programming skills, where do I start? People say learn C++ or Python but where can I learn this in a geographic context? Tutorials or anything would be very helpful, as would any information on languages/programmes to…
Will
  • 481
  • 1
  • 7
  • 7
34
votes
5 answers

Bulk load multiple shapefiles into PostGIS

I've got over a hundred data layers in shapefile format that I want to upload into a PostGIS database. They are all in the same projection, but represent different data layers so they do not have the same schema. What is the most time-effective…
RyanKDalton
  • 23,068
  • 17
  • 110
  • 178
34
votes
3 answers

Can QGIS preserve layers when exporting to PDF?

In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself). When I export from QGIS to PDF, I don't appear to have the option for this. Does QGIS support…
RyanKDalton
  • 23,068
  • 17
  • 110
  • 178
34
votes
4 answers

Python Script examples for geoprocessing shapefiles without using arcpy

I would like to use a Python script that is not based on arcpy to do things like query a shapefile by attributes, create new layer from selection, and calculate areas of a polygon and convert polygons to points. Anyone have any code examples of…
sherpas
  • 411
  • 1
  • 6
  • 6
34
votes
2 answers

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 report on the joined areas. I am maintaining a list of…
Geoconfused
  • 385
  • 1
  • 3
  • 6
34
votes
1 answer

Drawing perpendicular lines in PyQGIS

I have a situation like this: What I need to do is to connect each point to every line that is at most, let's say 200 m, away from the point. In other words, I need to draw a perpendicular line from each point to every line that is in the…
PeterBorook
  • 639
  • 6
  • 11
34
votes
3 answers

Which function for creating a POINT in PostGIS?

When defining a Point in PostGIS, when do you decide to use which of the following? ST_SetSRID(ST_MakePoint(lon,lat),4326) ST_SetSRID(ST_Point(long,lat),4326) ST_SetSRID(ST_GeomFromText('POINT(lon lat)',4326) ST_GeomFromEWKT('SRID=4326;POINT(lon…
Nyxynyx
  • 1,687
  • 4
  • 23
  • 35
34
votes
9 answers

Determining which US zipcodes map to more than one state or more than one city?

I'm using a zip code listing, and I am curious to know how many (or which) zip codes map to more than one US state or US city? For instance I know that Zip Code 42223 resolves to US Army, Fort Campbell which straddles the KY-TN state line. Oddly,…
Asking One
  • 381
  • 1
  • 3
  • 6
34
votes
4 answers

How to represent trend over time?

I have a time series of rasters where the cells of each raster represents some value at a certain time. I would like to generate a map that highlights the magnitude of positive or negative trends in this value over time for each cell. My somewhat…
user2856
  • 65,736
  • 6
  • 115
  • 196
34
votes
1 answer

How to create an accurate Tissot Indicatrix?

A Tissot Indicatrix is useful method for communicating at a glance the kinds of distortion a given projection is prone to (in the figure below, each of the red circles occupies the same area). I've been told that popular methods for generating TI's…
matt wilkie
  • 28,176
  • 35
  • 147
  • 280
34
votes
3 answers

How to easily edit attribute data using Regular Expressions?

I am writing a tutorial for MSc students that uses QGIS. One of the tasks requires the attribute data to be modified (see pdf draft of tutorial here if interested ). The question is how to get them to edit the attribute data. I know this question…
RobinLovelace
  • 4,254
  • 5
  • 32
  • 47
34
votes
2 answers

How can I conduct Geographically Weighted Principal Component Analysis using ArcGIS, Python and SPSS/R?

I am after a description/methodology for conducting a Geographically Weighted Principal Components Analysis (GWPCA). I am happy using Python for any portion of this and I imagine SPSS or R being used to run the PCA on the geographically weighted…
Michael Markieta
  • 5,411
  • 5
  • 36
  • 65
34
votes
3 answers

Uploading Geopackage contents to PostgreSQL

As a bit of background, we are looking to transition away from the use of shapefiles. We've already started using Geopackages for desktop work (QGIS / ArcGIS) but often have a requirement to upload data to our PostgreSQL databases. I'm aware that…
James Norris
  • 523
  • 1
  • 5
  • 8
34
votes
4 answers

Windows security warning (ActiveX) when clicking into fields in ArcToolbox tool?

I have been running ArcGIS 10.5 on my PC (Windows 10 Home) since December with no issues. This past week I have started to get ActiveX Security Warnings when I click into a parameter field in any ArcToolbox tool. Windows Security Warning An…
Midavalo
  • 29,696
  • 10
  • 48
  • 104
1 2 3
…
99 100