Trevor J. Smith
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in QGIS how to add (join?) another table to a layer
Accepted answer
6 votes

You've got a few options here. QGIS can natively open and process from CSV files so if your data is already in that format, you should be fine. Otherwise, you can export it to that format or install a ...

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Slope calculations appear to be 90 degrees off in ArcGIS 3D Analyst?
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5 votes

I think your error is a result of performing a slope calculation on a DEM that isn't in a projected Coordinate Reference System (CRS). The reason for performing a transformation/warping of your DEM is ...

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Strange output from QGIS Raster Terrain Analysis plugin
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4 votes

This is a really common error. You need to choose a projected coordinate system to warp your raster layers before doing any slope calculations. Since slope is determined by rise over run, If you ...

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Saving .shp data with symbolization changes
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4 votes

A more modern option that beats the traditional Shapefile and .qlr approach is to make use of the newer OGC-compliant GeoPackage standard. GeoPackages are the newest method of storing Vector and ...

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Spatially merging NetCDF climate grids?
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4 votes

I did some reading around and came across obscure CDO documentation for the collgrid function. With that, I was able to finally perform this series of merges in python by walking through files and ...

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Returning Multiple Nearest Neighbors
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3 votes

Following Joseph's suggestion, the answer lies in performing a distance matrix calculation using the PyQGIS algorithm designed for it. From here you can determine K-nearest neighbours and return a ...

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QGIS 2.8.6 raster calculator: cannot select cells which are below a value in a raster
3 votes

For the Raster Calculator, the logical equation is the first step needed in reclassifying a grid to identify which cells are being identified. The next step is assigning a new value to those cells (i....

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Cropping TIFF images based on GeoJSON bounding boxes in Python
2 votes

As @user30184 has mentioned, gdalwarp can perform exactly what you are looking for and can be called from the command line with the appropriate operations flags. If you are working from python (as has ...

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QGIS: Creating average of a precipitation multiple raster set?
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2 votes

If you want to take an average of all 12 images, the process is very simple. Within a raster calculator (this can be the calculator in the raster drop-down menu or the GDAL/GRASS/SAGA calculators in ...

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Installing PgPointCloud extension for PostgreSQL on Ubuntu Bionic
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2 votes

The first clue is that the website documentation you pointed to is specific to PostgreSQL-9.3 and an additional clue is that the date on the bottom of the page suggests it was last modified in 2015. ...

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Calculating distances between closest points of each polygon
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2 votes

I've also run into this problem before. Assuming that your polygons are uniquely named, it sounds like you simply need to perform a nearest-neighbour process to calculate a "Distance Matrix". The ...

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Ready made Contours from SRTM data?
2 votes

If you're looking for a continuous DEM spanning Canada and the USA, you might want to check out the EarthEnv DEM90 data set. It's reprocessed product from SRTM and ASTER and gap filled so the accuracy ...

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Free high resolution DEM or Lidar data for St Lucia
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2 votes

I've done some environmental consultation on that area and the best available resolution for a DEM there is probably the ASTER GDEM 30m. Even then, that data isn't processed/cleaned so you might run ...

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Making simple line more complex using QGIS?
2 votes

This isn't a python-script-based solution, but this will technically work: To add more nodes along along a line, you can use the "Densify Geometries" function specifying a distance or a number of ...

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Enabling preview in QGIS recent projects?
2 votes

Working from Linux here but the program is identical. The option you're looking for is under the general options -> "Project files" tab. The option for opening projects on launch can be set to the "...

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Copy geometry from one layer onto attributes of another?
2 votes

You've got a few options depending on how your data is organized. You can perform a table join/relate using a common field between your data sets (with the .dbf of shape file A as the table being ...

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Running IDW, but values are '<1' not 0.934 so they are Strings not Doubles
1 votes

You need to clean up your data prior to loading it into QGIS. I would do this either by removing the data points by giving them a specific value (either something negative (e.g. -9999) and set QGIS to ...

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Printed map has different scales for raster and vector layers in QGIS?
1 votes

I've seen this happen a bunch of times due to the same user error (I've made this mistake a few times as well). I think the problem is that your friend loaded their Shapefile first in another ...

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Global temperature maps
1 votes

Unsure if you still need this data but a great resource for annual climate data is directly through NASA/USGS data repositories. Beyond that NCAR holds a large amount of gridded environmental data, ...

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QGIS Desktop 2.14.0 with GRASS 7.03: Unable to edit
1 votes

Last I checked, QGIS can't be used to modify CSV, XLS, or ODS spreadsheets. If you import the spreadsheets and convert/export them to points or line-based shapefiles, only then will you be able to ...

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How to extract all pixel values in a raster file
1 votes

I'm not an Arc user, but the function you're interested is a statistics calculator for your raster file. Depending on the output you need, you could either use an ArcMap/Catalog tool to view a ...

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Plot image on map based on corner coordinates
1 votes

The process that you need to do in order to reproject your image is called georeferencing. For basic/linear georeferencing, the minimum number of points you need is 3 so if you have 4 corners you ...

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PyQGIS (3.2) and H5PY DLL problem
0 votes

I think your issue is that you don't have HDF5 built on your machine. All that h5py does is it creates a more pythonic API for accessing the compiled libraries on your machine. If you don't have the ...

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Create 1km Grid in QGIS from Canada Topo Data
0 votes

If your data is already projected properly into EPSG:26913 (NAD83/UTM13N) or something equivalent, then your problem might simply be that your project is set to WGS84. One easy way to fix this is to ...

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Problem with the ST_Area in PostGIS
-1 votes

I may be a bit rusty, but I think your problems are that the syntax is wrong (it looks like you're calling area as a method, which isn't a thing in SQL) and that you aren't nesting the transform ...

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