I have merged four different layers into one new one in QGIS, but I want this layer to have different information then the old layers. I want all the buffered 'islands' to have a different ID and a calculated area. However, now in the attribute table I just see four features, one for each layer that I merged. Is there a way to update the attribute table to consist of new features (one for each 'island')?
This is what the layer looks like:
And this is what the attribute table now looks like:
And this is what I want (the 5th and 6th column especially):
You must create a feature for each monopart geometry, you can achieve this using the 25.1.18.46. Multipart to singleparts tool, and then use the field calculator to get the area, you can find here how to calculate area Calculating polygon areas in shapefile using QGIS.
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I have a feature layer with points. I have three pages in my print composer. On one of my pages, I only want to show points that fall within a certain value range. First, I tried locking the style on the pages where I want to display all my points.
Then, I went to the Query Builder of the layer I want to select points from, and I created an expression to display only points from a range:
The problem is that this selection modifies the points shown on all my pages in print composer, even the ones where I locked the layers and style for layers. The only alternative solution I can think of is to select the points I want to show, create a new feature layer with those selected points, and then show that feature layer on my page in print composer. However I'd like to know if there's another way to do this without creating a new feature layer each time I want to filter the points I show in print composer.
There's another way. The points change because when you define a query, basically you define what features will be loaded to the project. So if you use categorized symbology you can define that some feature will be not displayed, but they will stay loaded in the project.
Here you can find how to use this type of symbology: Classifying Nominal Data
I have an existing map of ward in Chicago in Tableau:
I have a separate CSV file, linked to primary data source by Ward. It contains pairings of Long/Lat points. I can make a map of it by itself, but cannot find a way to place the points on this map. How would I do that?
If you want to overlay the dots to the existing area map you will need to use dual axis. Steps to follow are:
drag latitude (or longitude) from the csv datasource to rows (or columns); this will create another map
right click on the newly added measure and select "Dual axis"; this will overlap the two maps
in the marks box on the left you will be able to select different display settings for the two axis you will then have
You can also find a nice tutorial here
I need to train R-CNN on my dataset. Above Image is an example in which first column contain path to that image and second column contain coordinates of bounded box(ROI). How to get those coordinates in matlab. As my dataset is large so how those coordinates can be extracted by pointing manually.
for example if i am training R-CNN foe stop signs then second column contain coordinates of bounded box containing stop sign in whole image.
I do not know which version of MATLAB you are running, but I'm assuming it is fairly new (R2017a and later). Also, by 'how to get the coordinates', I assume you mean 'how to determine' or 'how to assign' the coordinates.
I believe what you need to do is to use one of the image labeling Apps called
imageLabeler
to annotate rectangles in your training images. You either do this manually if that's amenable, or you need to use automation algorithms if you already have a detector that does something similar. See this page for more details:
https://www.mathworks.com/help/vision/ug/create-and-import-an-automation-algorithm-for-ground-truth-labeling.html
Once you have the results of labeling stored in a groundTruth object, you would need to use something like objectDetectorTrainingData to create the table you are looking for.
See https://www.mathworks.com/help/vision/ug/train-an-object-detector-from-ground-truth-data.html for more details.
I have a problem where my buffer lines do not dissolve with the rest of the data. I want the buffer lines to "open" where they cross other data, right now it looks like the buffer data is layered on top of the other data.
In the picture I have pointed out a place where I would like the buffer to "merge" with the rest. There are plenty of those places, I have tried the dissolve but this is the only result I have gotten. Picture of the problem.
What you want to do is dissolve but you will need to dissolve the polygons based on a field from the attribute table. If all of the shapes that you want to merge have the same value in that field of the attribute table you'll be able to utilize dissolve.
Please see this post from gis.stackexchange:
Merge intersecting polygons into one which are part of the same feature
I have a worksheet in tableau which uses shapefiles of a state at district level. But when I bring it into the view, and hover over anything, all of it gets highlighted. I found out the Geometry is set to MULTIPOLYGONS instead of POLYGONS. How can I convert multipolygons to polygons so I can hover over each district and get their details in the tooltip?
Shapefiles are normally constructed with one Multipolygon per district (at least for districts that need more than one polygon to describe the area as many do). So when you select a single district, you get all the geometry associated with the district. This is intentional and the right behaviour for highlighting districts (or whatever unit you are working with).
What is probably happening for you is that you have displayed a map but haven't put the district identifier onto the Tableau "detail" shelf. In this case the *whole" map will highlight. This has nothing to do with Multipolygons. It is a deliberate choice in Tableau to allow for the possibility of maps containing multiple hierarchical areas.
In the UK, for example, you can get shapefiles with low level census areas called LSOAs. But the data will also contain how these fit together into higher-level areas (MSOAs, local authorities, parliamentary constituencies etc.). Using the low-level shapefile with the higher-area information is possible by dragging the names of the higher-level areas into the details shelf making them the unit of analysis for the map.
If you don't drag any area name into the detail shelf, Tableau will assume the whole map is the unit for aggregation and will highlight everything.
So fix the problem by dragging the unit names or identifiers for your districts to the shelf and everything will work.