11
votes
QGIS: Compare two concatenate fields and add similar strings to new column
It can be achieved by converting the RefSpecies and Sightings strings to arrays and checking whether each element of the Sightings array appears in the RefSpecies array:
-- create arrays of the `...
- 17.9k
7
votes
QGIS: Compare two concatenate fields and add similar strings to new column
Use field calculator to:
Create your custom function (Function editor tab):
@qgsfunction(args="auto", group='Custom')
def myFunc(f1, f2, feature, parent):
l1 = [x.strip() for x in f1....
- 1,150
4
votes
Accepted
From areas of several species ranges (polygons) to a map (raster) expressing the count of overlapping polygons
Either do what Spacedman suggests (rasterize and sum) or work directly on the polygons:
library(raster)
sp1 <- spPolygons(rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60), c(-180,-20)), attr=...
- 11.1k
4
votes
How to identify all species observed in each cell of a research grid
On the grid layer, create a new attribute with Field calculator and the following expression. It generates you a text field for each grid cell, listing the species that are located in this cell.
Be ...
- 75k
3
votes
How to identify all species observed in each cell of a research grid
One way of doing this:
First run Join Attributes by Location (vector menu>Data Management Tools) - this will create a memory layer called Joined Layer.
Then save Joined Layer as a geopackage. In ...
- 1,746
2
votes
Calculating kernel density home ranges of animals in QGIS
In the Processing Toolbox click the cogs then choose "Open Existing Model...", then hit the run button.
Or in the Processing Toolbox click the cogs then choose "Add Model to Toolbox...&...
- 11.3k
2
votes
Extracting raster values from polygon perimeters using ArcGIS Spatial Analyst?
If you are wanting to extract the pixel values for a polygon boundary rather than the interior area, then you need to convert your polygons into polylines. You don't actually state what GIS system you ...
- 44.6k
2
votes
Accepted
Color grid if values in grid exceed threshold - species distribution in QGIS
Use the Field Calculator to add an integer field called "present" with this expression:
"species_ct_A"*"value_A" + "species_ct_B"*"value_B" + "species_ct_C"*"value_C" + "species_ct_D"*"value_D" = 12
...
- 25.1k
1
vote
Counting unique species in polygon layer and buffer
If you have two polygon layers which you want to overlay then count points with some unique attribute try:
Intersect the polygon layers
Intersect output (as overlay layer) with points (as input layer)...
- 77.9k
1
vote
SDM: Dealing with coarse environmental data
The issue you have is that your data covers a very small area, such that you couldn't possibly make any inference about the species response to different climate variables.
Were there any other ...
- 2,176
1
vote
SDM: Dealing with coarse environmental data
Getting temperature estimates at finer resolution than 1 km is not likely to happen without you placing your own temperature loggers around your study site. You're going to have to look into using ...
- 837
1
vote
Species ranges into fishnet grids
First make sure your fishnet layer has a unique ID field, we'll assume it's called Id.
I would assume that each feature in your fishnet layer has the same area, but just in case calculate the area for ...
- 984
1
vote
Species ranges into fishnet grids
Create a vector grid with required settings(extent, spacing) and choose output type as polygon
vector > research tools > vector grid
perform an intersection with the species distribution layer.
...
- 441
1
vote
Kriging predictions for presence only data with Maxent
Interesting method to use; have you considered running the model with equal numbers of pseudo absences and then increasing or decreasing the proportion of known absences to pseudo absences to see if a ...
- 2,176
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