Remove 0 Values From Raster Qgis

js If you are looking for a tool to easily create 3D visualizations of your geodata, look no further! Qgis2threejs is a plugin by Minoru Akagi which exports terrain data combined with the map canvas image and optional vector data to an html file which can be viewed in 3D in any web browser which supports WebGL. There are 14 possible land cover categories but for simplicity in this example, I'm going to limit my data to water (raster value 0), roughly green areas (1-8, 10,11), shrubland (9) and urban (13). The contour area was set to pixel value = 0 and I have a nodata value of -32768. reclass has been derived is only possible if the original map is removed first. Each pixel in the raster has a value assigned. The General menu displays basic information about the selected raster, including the layer source path, the display name in the legend (which can be modified) and the number of columns, rows and No-Data Values of the raster. To reproduce the error: load the attached calculated raster in the TOC. All Answers ( 4) In QGIS you can use the 'Point sampling tool' plugin, or in ArcGIS you can use 'Extract values to points' from the spatial analyst tool box. This post shows how the style works which - when applied to the point layer - wil make sure that only towns and (when zoomed in) villages will be marked and labeled. QGIS 다뤄보기 II-2. QGIS is an official project of the Open Source Geospatial Foundation (OSGeo). Quest'esercitazione è stata realizzata per GRASS 6. QGIS plugins web portal. To launch QGIS in Windows, click Start > All Programs > Quantum GIS Brighton > QGIS Desktop 2. Figure 3 Discrete approximation to Gaussian function with =1. Multiple formats of raster images are supported, and the software can georeference images. For the second solution, you can use the information tool on the raster layer, note the raster value in the black and white areas you want to remove, and add those as NODATA in the layers transparency tab. 0, o Renderizador de Paletas raster existente para rasters foi adaptado para permitir um estilo fácil de camadas de varredura discretas, como capas de terras ou rasters booleanos. A cell is assigned the NoData value if there is either no information or insufficient information about the characteristics of the location it represents. 0 (OSGeo4W setup, advanced installation with qgis-grass-plugin 1. bitmap, image file to display as a marker. You would have to chain these if you want to reclass several values. Exporting the river alone as a raster, then creating a polygon out of that raster, however I would have to reasign coordinates for this new polygon, which would bring some inacuracies. QGIS supports shapefiles, coverages, personal geodatabases, dxf, MapInfo, PostGIS, and other formats. qpj (QGIS projection file) to be associated with the shapefile in order to interpret the EPSG:3857 projection correctly. The new cropped layer will be loaded into QGIS. Picture 2 Raster based terrain analysis tool This picture shows the QGIS raster based terrain analysis tool menu which is a fairly straight forward tool which allows you to perform the 4 types of raster based terrain analysis techniques: slope, aspect, ruggedness index and total curvature. In this example I’m calculating a percentage, with fields and sum of all values (833944) for dynamically give sizes to the pie. Elevation layer [raster] Digital Terrain Model raster layer. To open a URL that is not relative to the installed QGIS documentation, set useQgisDocDirectory to false. The ogr2ogr utility does not create the. org and install the latest version. There are two ways to define how the values will be reclassified in the output raster: RemapRange and RemapValue. A cell is assigned the NoData value if there is either no information or insufficient information about the characteristics of the location it represents. I want to ask what probably is a basic question about the way in which R and QGIS import raster files. When I import it into R, using the "raster" function of the raster package, I get this range of pixel values:. (I created it by rasterizing a polygon layer. The raster image marker symbology permits customization of width, height, image ratio, rotation, and opacity. Now, users can select the renamed "Paletted/Unique Values" renderer and click the "Add Unique Values" button to load all unique raster values from the layer. This is an attempt to partially fix #30041 Nyall Dawson 2019-06-12 If the first layers loaded into a project is non-valid (e. Select the field and values then tap on all uniques and select the desired value. Each beam radiation map was filtered: if pixel value equal to 0 then “sun-no”, otherwise “sun-yes” (what my friends wanted to achieve; effectively a conversion into a binary map). Input layer [raster] Input raster file. The Raster Calculator tool allows you to create and execute a Map Algebra expression that will output a raster. If there are values associated with a RasterLayer object (either in memory or via a link to a file) these are lost when you change the number of columns or rows or the resolution. This value may be based on the elevation of the cell, flood water depth, or soil quality. No change would take place to the values of other pixels. It seems for me that this is a task for the raster calculator (set value of pixels <=0 to "nodata") or a reclassification (set value of pixels <=0 to "nodata" and keep all other values) but I dont know how. Raster Histogram Pixel. Sampling raster values at point locations in QGIS On February 15, 2010 July 1, 2014 By pvanb In Data handling , GIS , GIS software , QGIS Recently I received an excel file with the coordinates of 144 vegetation sample plots, with the request to get the altitude values for the plots. Without this parameter it is not possible to remove collars surrounding input raster which may overlap with other input rasters. It has a clean interface, it's easy to use, and it just works. ArcGIS Generalization toolset has the nibble and expand tools to fill in NoData holes. Otherwise the conditional expression evaluates to 0, which sets the raster value to 0. Jun 25, 2017 · I have a time series of raster images read as a raster stack using raster package in R where each raster has the calculated value ranges from 0 - 100. Under the Raster menu, go to Projections and select Warp. more than once per year. wher band 0 and 1 = 0)? I have tried to clip the image with a polygon but the black areas still remain. For many people, discovering QGIS is the end of their search for an ArcGIS alternative. http://changelog. Sum values of Raster objects by row or column. However, the question was not to calculate irradiance raster maps in Wh/m^2 but simply "sun-yes" or "sun-no". When the LTLST dll loads, it registers a window class (LTIMGLISTCLASS) for you. Use the default value of 0. However, if the field is of type floating point and the values are expressed as integers, then the output raster will be integer. Open a url in the users browser. Basic rules for writing Python scripts for Processing Toolbox in QGIS Posted on April 12, 2017 November 8, 2017 by howtoinqgis One of the most powerful QGIS tools is the possibility to create custom Python codes and then adding them to the Processing Toolbox. 3D viz with QGIS & three. The data component of the ESRI ASCII raster follows the header information. Right-click on the Brazil_mosaic_clipped layer and select Properties. Raster Interpolation is a QGIS plugin. Go to the Transparency tab, and add 0 as an Additional no data value. The number of elements of this list must be the number of axis of the CRS. Default: 1. As the Target SRS you need to choose your defined target coordinate system. Open a url in the users browser. It is based on R, a statistical programming language that has powerful data processing, visualization, and geospatial capabilities. QGIS 다뤄보기 II-2. In this case, you may want to change NoData values to 0. Enter the formula ifelse(gt(a,0), (a), b) The formula reads as follows "if a is >0 then use the value from a else use the value from b". The goal is to vectorize the mask and use it to clip the original data. The raster image marker symbology permits customization of width, height, image ratio, rotation, and opacity. So no matter what you do NaN/NULL in any input become NULL in output. Cell size of raster data The level of detail (of features/phenomena) represented by a raster is often dependent on the cell (pixel) size, or spatial resolution , of the raster. Translate OS "orientation" field (integer angle in 1/10 degrees) to "angle" as a float. Now, since we know the color value of our no-data area on our raster, lets learn how to remove the black/white or any color no-data values on raster images in QGIS using these step-by-step guide. How To: Convert NoData values to other values for raster data Summary. This information is stored as a QGIS project file and has an extension of '. Select an output file to save the raster after the alignment, the resampling method and if the tools need to Rescale values according to the cell size. value of 0; changed default value. Nodata value, leave as none to take the nodata value from input [string] Defines a value that should be inserted for the nodata values in the output raster. This tutorial shows you how to use Quantum GIS (QGIS) to create simple maps and complete basic spatial analysis tasks. In QGIS you will need a RasterCalc plugin. Robin's Blog How to: Set raster values to NoData easily in ArcGIS 10 May 2, 2012. QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS) - qgis/QGIS. This tutorial is explain how to to Mask raster with raster mask which contain 0 for no data value and 1 for data values. Click on the arrow next to PostGIS and open the list. qpj file by default because ogr2ogr is a general utility that is used with a lot of different programs, not just QGIS. Input layer [raster] Input raster file. Load in QGIS when done is often a good choice. The Raster Calculator tool allows you to create and execute a Map Algebra expression that will output a raster. Robin's Blog How to: Set raster values to NoData easily in ArcGIS 10 May 2, 2012. 00108026 and 0. Map styling for compositions. A 1-bit raster contains two values (zero and one). In QGIS project properties, the user can defined: which part of the project (all the project, layer groups or layers) has to be published through WMTS standard; the min scale of the tiles; QGIS Server reused the CRS defined in the WMS for WMTS. Remember from the readings, most raster operations return No Data as output if any part of the input is No Data. Nodata value, leave as none to take the nodata value from input [string] Defines a value that should be inserted for the nodata values in the output raster. QGIS plugins add additional functionality to the QGIS application. To make experimentation with the inputs and parameters easier, use the Topo to Raster dialog box to create an output parameter file, which can be modified in any text editor and used as input to the Topo to Raster by File tool. Statement has three arguments: raster to compare;. To do that, first click on the pencil icon on the bottom row of icons to enter Editing mode. Vector layers use the three basic GIS features - lines, points, and polygons - to represent real-world features in digital format. This tool is intended for combining classifications in order to get a raster where each value corresponds to a combination of class values. Here is an image of what I am working on (white = 1. I assume that -9999 is the value assigned to the NULL data pixels. Working with the Raster Calculator The Raster Calculator provides you a powerful tool for performing multiple tasks. QGIS plugins web portal. The union algorithm can be now run with just a single input layer in order to resolve any overlaps among the layer's. If you run Feature Vertices to Points you won't be extracting all the cells underneath the line, unless you densify the line in advance to the resolution of the raster you wish to extract from. Use this option to remove the unwanted values created around the raster data. The Stream Raster Grid is used as the source for the stream network. Delete 0 value on Raster - posted in GIS: Does anyone know of an easy way to delete the zero value for a raster in ArcMap 10? I've created a raster of 1s and 0s and multiplied it by my NED. In these raster files, the parameter that is being represented is encoded as the pixel values of the raster. 0" as version 3. The raster image marker symbology permits customization of width, height, image ratio, rotation, and opacity. 001 increments). To open a URL that is not relative to the installed QGIS documentation, set useQgisDocDirectory to false. 0, the existing raster Paletted Renderer for rasters was adapted to allow for easy styling of discrete raster layers, such as landcover or boolean rasters. How To: Limit the values of a raster with Spatial Analyst Summary. Comparison operators allow to perform pixel-wise compare raster band with some value or another raster band. Viewing in QGIS Gridded Surfaces. The first method to query raster values is using We can remove an entry from Authentication Database using it. When the LTLST dll loads, it registers a window class (LTIMGLISTCLASS) for you. Lastly, expand the Background section and set the Color Alpha Value to 0. QGIS (previously also known as Quantum GIS) is a free (GNU GPL v2) and open source GIS application enabling the user to visualize, manage, edit, analyse data, and compose printable maps. For the first solution, you might clip your data by a polygon layer of the red line. 5 can be considered ice. Rasters are grids of pixels that have a specific value assigned to them. There are two ways to define how the values will be reclassified in the output raster: RemapRange and RemapValue. Now, users can select the renamed "Paletted/Unique Values" renderer and click the "Add Unique Values" button to load all unique raster values from the layer. How to Fill NoData for Raster Data There are a couple of options to fill NoData cells for a raster image. By doing mathematical operations on these values, one can do some interesting analysis. shp) from the file type menu, select Rivers_in_Southeast_Asia. I thing the polygon word is not really appropriate but the tool should do what you want without going through heavy polygon vectorisation. Return a raster which values are the result of a PLPGSQL user function involving a neighborhood of values from the input raster band. Before generating the query you can check attribute table in QGIS. Let's open an existing QGIS project and have a look at how it works. Symbolizing values of NoData in raster datasets. Select the field and values then tap on all uniques and select the desired value. QGIS Issue Tracking. ST_Reclass — Creates a new raster composed of band types reclassified from original. This value may be based on the elevation of the cell, flood water depth, or soil quality. The Field parameter allows you to choose which attribute field of the input raster dataset will become an attribute in the output feature class. Now, users can select the renamed "Paletted/Unique Values" renderer and click the "Add Unique Values" button to load all unique raster values from the layer. gml Command line option --snapshot This option allows you to create a snapshot in PNG format from the current view. 1 has the same "3. Clipping extent [extent] Extent that should be used for the output raster. Select an output file to save the raster after the alignment, the resampling method and if the tools need to Rescale values according to the cell size. So a subsequent filtering had to be applied. Python support was first introduced in QGIS 0. I'd like to reclass a raster that contains just cells with values nodata and 1. For interaction with QGIS environment, there is qgis. Translate OS "orientation" field (integer angle in 1/10 degrees) to "angle" as a float. You can use Reclassify tool. ArcGIS Generalization toolset has the nibble and expand tools to fill in NoData holes. I am trying to do my best to give explanation about QGIS Python programming with some examples. For this example, choose ESRI Shape (*. L_INT IntelligentDownScaleExample(L_VOID) { L_INT nRet; BITMAPHANDLE LeadBitmap; // Bitmap handle to hold the loaded image. Using a temperature raster as an example, when you group values from [-37. But this new raster image is different, because the values of each pixel don't represent colours, but rather altitude, and QGIS doesn't know automatically how to display it. And for QGIS 1. QGIS is an official project of the Open Source Geospatial Foundation (OSGeo). The highest values corresponding to the most dense vegetation cover. The General menu displays basic information about the selected raster, including the layer source path, the display name in the legend (which can be modified) and the number of columns, rows and No-Data Values of the raster. From here, you can follow these exact same steps for vectorization. 5 can be considered ice. The rgdal package is normally installed with your installation of raster. To remove the NoData values, this entry is intended to generate a surface that contains only the values corresponding to the raster variable. In these raster files, the parameter that is being represented is encoded as the pixel values of the raster. If you can't find what you're looking for here, leave us a message at forum. However, if the field is of type floating point and the values are expressed as integers, then the output raster will be integer. Often times, during spatial analysis using raster data, there might be a need to change a particular value in the data to different value to use the raster in the next analytical operation. The following Raster Calculator expression uses a conditional statement and focal statistics to replace no data values within a raster with a value statistically derived from neighboring. Mask pixel values in Raster image QGIS Punwath Prum. Color balancing. While a 8-bit raster ranges from 0-255 (256 values in total). 4 The screenshot above illustrates how to get the layer currntly selected in the layer list, show its ID and optionally, if it is a vector layer, show the feature count. Default: 0,1,0,1. Welcome to DroneDeploy's Support Documentation! Here, you'll find comprehensive guides to get started with DroneDeploy, as well as tips for mapping. Using the "-r" switch it will on-the-fly project to the image's projection before extracting a value from the raster. Bug report #14021: changing a value in the advanced settings editor makes qgis crash Bug report #14037 : frequent crash when editing data in relation forms (standard relation form-widget, generated by qgis). Before generating the query you can check attribute table in QGIS. 7] as 1, you are turning it into a discrete raster. Numerical values and mathematical operators can be added to the expression by clicking the respective buttons in the tool dialog box. Click the symbol that represents background (usually with a. Statistics must exist for the rasters within a mosaic dataset when using color balancing. There are two ways to define how the values will be reclassified in the output raster: RemapRange and RemapValue. Tutorial - Qgis Build No Data Mask ONF International. Parameters:. QGIS has some basic analysis capabilities built-in via Raster. Under the Raster menu, go to Projections and select Warp. Serval is available from QGIS plugin repository. In this example, where the value of the input conditional raster is greater than or equal to 1500, the output value will be 1, and where it is less than 1500, the output value will be 0. The raster is rendered as in grayscale, where darker pixels indicate lower values and lighter pixels indicate higher values. Go to the Transparency tab, and add 0 as an Additional no data value. In ArcMap, in the table of contents, right-click the raster layer from which you want to remove the background and click Properties. tif files and parse them to hexagons. There are setting in layer properties and bands etc, but I don't know how to do it and have been unable to find a good explanation. I have a single band-raster. The highest values corresponding to the most dense vegetation cover. QGIS has some basic analysis capabilities built-in via Raster. Be careful not to specify a value that is also valid within the dataset. But before we are discussing about drawing contour lines in QGIS, let's start talking a little bit about the concept of contour line, what contour line definition is, contour lines characteristics and and how the method in drawing contour line. I would like to remove the clouded areas from the images. I assume that -9999 is the value assigned to the NULL data pixels. The unique index on column '%1' is unsuitable because Quantum GIS does not currently support non-int4 type columns as a key into the table. 0: Bug report #12498: Python console crash QGIS if undocked while autocompletion active. Get ozi map/raster tiles file The tools described here differ by the output file, some create calibrate raster files where map file will be extracted, others create only map files that will be used to extract raster files. Does anyone have any clue how to solve this?. It is useful in the middle of a script, to recover the resources held by accessing the dataset, remove file locks, etc. On the Appearance tab for a raster layer, you will find essential raster functionality to adjust the display and appearance of your imagery. Various spatial analysis applications require raster NoData cells to be factored into an analytical operation. When Extract Values to Points is used on a multiband raster, the RASTERVALU field will contain values from the last band of the input raster. Adding the. Data formats include downloadable shapefiles, web services, KML files and our basemaps in shapefile format. Many thanks. STATISTICAL OPERATORS calculate statistics for each cell by using a statistical function such as minimum, maximum, average or median. How To: Convert NoData values to other values for raster data Summary. Welcome to the Spatial Analysis Using Quantum GIS Course Welcome to the Spatial Analysis Using Quantum 0 In Progress 0 Topographic with Raster Data Analysis. PostGIS Raster Released with PostGIS 2. I assume that -9999 is the value assigned to the NULL data pixels. remember in Raster calculator (and other QGIS Tools) is that when you chose the file the 1st file is internally "known as" "a" and the 2nd file is "known as" "b" and so forth. There are a few ways to go about this task. To remove the slivers, we specify that all polygons with an area less or equal to 25,000 m 2 should be joined to the neighboring polygon with the largest area (see right panel of Figure 9. Here’s a quick run-down on two nice new styling options which I’ve recently added to QGIS 2. We need to clip this again. Elevation layer [raster] Digital Terrain Model raster layer. worldwide. Often times, during spatial analysis using raster data, there might be a need to change a particular value in the data to different value to use the raster in the next analytical operation. Users can directly edit raster cell values using Serval plugin in QGIS. This tool is intended for combining classifications in order to get a raster where each value corresponds to a combination of class values. As an example to quickly enter the "f" (multiplication factor applied to the boundary values) attribute for all "CN" (connection) type boundaries Open an attribute table for the layer, to do this right click on the layer in the layer control panel and select Open Attribute Table. Generate a PDF map if you like. 0 was released way back in September 2013. The highest values corresponding to the most dense vegetation cover. Elevation data (DEM) is also distributed as raster files. Pansharpening is made in two steps: 1) resampling of the low resolution raster via Superimpose sensor tool; 2) pansharpening using Pansharpening tool. Adding the. This creates the mask on the fly. 7] as 1, you are turning it into a discrete raster. The vegetation has positive NDVI values, generally between 0. 0: Bug report #12498: Python console crash QGIS if undocked while autocompletion active. 5 can be considered ice. General Features. If a field is not specified, the cell values of the input raster (the VALUE field) will become a column with the heading Grid_code in the attribute table of the output feature class. com or write us at [email protected] ) Now I want to change all nodata values to 0, but I cannot find any way to do this. Right-click on the Brazil_mosaic_clipped layer and select Properties. 0 Bug report #7636 : Raster transparency color-from-canvas picker not working on Mac Bug report #7639 : important data loss regression: data entered into newly created column(s) lost when saving changes. For bpol dan rmdupl we can just give a dummy value 0, but for remove area, I gave it 3. 8 is also a special release because it includes so many great new features,. You can change this value in this field. First, we’ll substitute 0 values for No Data values in the Valley3 data set. Be careful not to specify a value that is also valid within the dataset. Bug report #14229: Raster in projected CRS is not rendered in geographic CRS if the extent exceeds -180,-90,180,90: Bug report #14589: GetCapabilities gets cached in a confusing way (even when QGIS cache is set to 0) Bug report #14597: Grid Interpolation requires Real data type with decimals for Z value. On the Appearance tab for a raster layer, you will find essential raster functionality to adjust the display and appearance of your imagery. Loading Watch Queue QGIS - Rasterize - Vector to Raster by specifying desired pixel length Bhaskar Reddy Pulsani. This creates the mask on the fly. 1 has the same "3. 0 Bug report #7636 : Raster transparency color-from-canvas picker not working on Mac Bug report #7639 : important data loss regression: data entered into newly created column(s) lost when saving changes. You could use reclassify tool or raster calculator 1. It runs on Linux, Unix, Mac OSX, Windows and Android and supports numerous vector, raster, and database formats and functionalities. Select the field and values then tap on all uniques and select the desired value. How to use Serval. Click on the arrow next to PostGIS and open the list. the buffer size can be dynamically calculated for each individual feature buffered. For this example, I have nationwide census tracts and a North Carolina state boundary, and I want a layer of just the census tracts in North Carolina. QGIS plugin: Samples polygon attributes and raster values from multiple layers at specified sampling points - borysiasty/pointsamplingtool. 0 (OSGeo4W setup, advanced installation with qgis-grass-plugin 1. Several of the "Stream Network Analysis" tools produce this type of grid. For QGIS 2. This value may be based on the elevation of the cell, flood water depth, or soil quality. Raster Histogram Pixel. QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS) - qgis/QGIS Remove NaN values from raster before hash calculation. Without this parameter it is not possible to remove collars surrounding input raster which may overlap with other input rasters. Again, use AsPPM for the input attribute. remember in Raster calculator (and other QGIS Tools) is that when you chose the file the 1st file is internally "known as" "a" and the 2nd file is "known as" "b" and so forth. While processing some data at work today I had an issue where I had a raster dataset in ArcGIS, where all cells with invalid data had been set to 9999. To do this, go to the "Layer" at the top, select "Add Raster Layer" and select your DEM file. So no matter what you do NaN/NULL in any input become NULL in output. In this example I’m calculating a percentage, with fields and sum of all values (833944) for dynamically give sizes to the pie. I only want polygons for pixels with value 1. This will effectively remove the background cells by making them transparent since you are only interested in creating raster cells for areas that are either urban or park in this exercise. In this case, QGIS will assume a single pixel is 1 metre square and it will place the Scanned map at 0 o North, 0 o West in the Atlantic Ocean south of Ghana. Since that release so much has changed in QGIS… a quick glance over the release notes for 2. Using the "-r" switch it will on-the-fly project to the image's projection before extracting a value from the raster. Sum values of Raster objects by row or column. As the Target SRS you need to choose your defined target coordinate system. By doing mathematical operations on these values, one can do some interesting analysis. Two ways to change NoData to zero in ArcGIS are as follows: Reclassify Tool. If you can't find what you're looking for here, leave us a message at forum. Hence it shows every pixel in the image as grey, even if the values in each pixel are different. Remove all; Disconnect; The next video is starting stop. If a field is not specified, the cell values of the input raster (the VALUE field) will become a column with the heading Gridcode in the attribute table of the output feature class. Loading Watch Queue QGIS - Rasterize - Vector to Raster by specifying desired pixel length Bhaskar Reddy Pulsani. Data format. The raster has been given values from 0-360 depending on the slope aspect. Is there a syntax update that I am missing?. To do that, first click on the pencil icon on the bottom row of icons to enter Editing mode. Select all the records except "NoData" and click Delete Entries For "NoData", Define the new values to 0. It browses a vector layer of points, interpolates at their position the value of a raster layer and save the value in a chosen field of the vector layer. Larger values result in greater smoothing, but smaller values may show finer details and variation in point density. 3) or to switch it off. To find out about the default values, run get_args_man(). This little feature was suggested by Mathieu Pellerin, who is always pushing the boundaries of QGIS’ cartographic tools and coming up with great ideas for new styling features (you can check out some of his work via Flickr). This value is the population density for that grid. QGIS plugin: Samples polygon attributes and raster values from multiple layers at specified sampling points - borysiasty/pointsamplingtool. 0 and Adding Layers | Programming Historian. Go to properties of the raster, then go to style, select singleband pseudocolor and generate the desired pixel-value/color associated (manually or generated automatically using the several options that Qgis have to do this) with only one requirement: the pixel-values associated must be integers. reclass map is not a true raster map layer. Two ways to change NoData to zero in ArcGIS are as follows: Reclassify Tool. Figure 3 Discrete approximation to Gaussian function with =1. All other bands are returned unchanged. After you click Ok and run the translation, QGIS should add your map to canvas automatically and you should see the raster on top of the OpenStreetMap layer in the correct location. Japanese French Polish Deutsch. Download it from QGIS. QGIS has some basic analysis capabilities built-in via Raster. 7] as 1, you are turning it into a discrete raster. There are setting in layer properties and bands etc, but I don't know how to do it and have been unable to find a good explanation. Open a url in the users browser. nRet=L_LoadBitmap(MAKE_IMAGE_PATH(TEXT. The contour area was set to pixel value = 0 and I have a nodata value of -32768. General Features. In these raster files, the parameter that is being represented is encoded as the pixel values of the raster. You would have to chain these if you want to reclass several values. Both examples work well, but they are terribly inefficient and won't process a really big raster. The result will be a raster with all pixels that match condition set to 1 and all other pixels set to 0. You can use Reclassify tool. The fact-checkers, whose work is more and more important for those who prefer facts over lies, police the line between fact and falsehood on a day-to-day basis, and do a great job. Today, my small contribution is to pass along a very good overview that reflects on one of Trump’s favorite overarching falsehoods. Namely: Trump describes an America in which everything was going down the tubes under  Obama, which is why we needed Trump to make America great again. And he claims that this project has come to fruition, with America setting records for prosperity under his leadership and guidance. “Obama bad; Trump good” is pretty much his analysis in all areas and measurement of U.S. activity, especially economically. Even if this were true, it would reflect poorly on Trump’s character, but it has the added problem of being false, a big lie made up of many small ones. Personally, I don’t assume that all economic measurements directly reflect the leadership of whoever occupies the Oval Office, nor am I smart enough to figure out what causes what in the economy. But the idea that presidents get the credit or the blame for the economy during their tenure is a political fact of life. Trump, in his adorable, immodest mendacity, not only claims credit for everything good that happens in the economy, but tells people, literally and specifically, that they have to vote for him even if they hate him, because without his guidance, their 401(k) accounts “will go down the tubes.” That would be offensive even if it were true, but it is utterly false. The stock market has been on a 10-year run of steady gains that began in 2009, the year Barack Obama was inaugurated. But why would anyone care about that? It’s only an unarguable, stubborn fact. Still, speaking of facts, there are so many measurements and indicators of how the economy is doing, that those not committed to an honest investigation can find evidence for whatever they want to believe. Trump and his most committed followers want to believe that everything was terrible under Barack Obama and great under Trump. That’s baloney. Anyone who believes that believes something false. And a series of charts and graphs published Monday in the Washington Post and explained by Economics Correspondent Heather Long provides the data that tells the tale. The details are complicated. Click through to the link above and you’ll learn much. But the overview is pretty simply this: The U.S. economy had a major meltdown in the last year of the George W. Bush presidency. Again, I’m not smart enough to know how much of this was Bush’s “fault.” But he had been in office for six years when the trouble started. So, if it’s ever reasonable to hold a president accountable for the performance of the economy, the timeline is bad for Bush. GDP growth went negative. Job growth fell sharply and then went negative. Median household income shrank. The Dow Jones Industrial Average dropped by more than 5,000 points! U.S. manufacturing output plunged, as did average home values, as did average hourly wages, as did measures of consumer confidence and most other indicators of economic health. (Backup for that is contained in the Post piece I linked to above.) Barack Obama inherited that mess of falling numbers, which continued during his first year in office, 2009, as he put in place policies designed to turn it around. By 2010, Obama’s second year, pretty much all of the negative numbers had turned positive. By the time Obama was up for reelection in 2012, all of them were headed in the right direction, which is certainly among the reasons voters gave him a second term by a solid (not landslide) margin. Basically, all of those good numbers continued throughout the second Obama term. The U.S. GDP, probably the single best measure of how the economy is doing, grew by 2.9 percent in 2015, which was Obama’s seventh year in office and was the best GDP growth number since before the crash of the late Bush years. GDP growth slowed to 1.6 percent in 2016, which may have been among the indicators that supported Trump’s campaign-year argument that everything was going to hell and only he could fix it. During the first year of Trump, GDP growth grew to 2.4 percent, which is decent but not great and anyway, a reasonable person would acknowledge that — to the degree that economic performance is to the credit or blame of the president — the performance in the first year of a new president is a mixture of the old and new policies. In Trump’s second year, 2018, the GDP grew 2.9 percent, equaling Obama’s best year, and so far in 2019, the growth rate has fallen to 2.1 percent, a mediocre number and a decline for which Trump presumably accepts no responsibility and blames either Nancy Pelosi, Ilhan Omar or, if he can swing it, Barack Obama. I suppose it’s natural for a president to want to take credit for everything good that happens on his (or someday her) watch, but not the blame for anything bad. Trump is more blatant about this than most. If we judge by his bad but remarkably steady approval ratings (today, according to the average maintained by 538.com, it’s 41.9 approval/ 53.7 disapproval) the pretty-good economy is not winning him new supporters, nor is his constant exaggeration of his accomplishments costing him many old ones). I already offered it above, but the full Washington Post workup of these numbers, and commentary/explanation by economics correspondent Heather Long, are here. On a related matter, if you care about what used to be called fiscal conservatism, which is the belief that federal debt and deficit matter, here’s a New York Times analysis, based on Congressional Budget Office data, suggesting that the annual budget deficit (that’s the amount the government borrows every year reflecting that amount by which federal spending exceeds revenues) which fell steadily during the Obama years, from a peak of $1.4 trillion at the beginning of the Obama administration, to $585 billion in 2016 (Obama’s last year in office), will be back up to $960 billion this fiscal year, and back over $1 trillion in 2020. (Here’s the New York Times piece detailing those numbers.) Trump is currently floating various tax cuts for the rich and the poor that will presumably worsen those projections, if passed. As the Times piece reported: