Tagged Questions

Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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3
votes
2answers
129 views

Point file to raster

I have a point file of trees in my study area, which includes the attributes of each tree. Each tree also has a crown radius associated with it. I need to summarize the attributes of these points ...
4
votes
3answers
416 views

query raster cell values by point

I have a binary raster (0s and 1s) that I need to query given a set of point coordinates. This is easy enough to do with gdal (gdallocationinfo), but where it get's complicated is that I also need to ...
1
vote
1answer
250 views

How to convert a shapefile polygon to raster in C#

Does anybody know a way to convert a polygon (vector) in a shapefile to raster data WITHOUT using ArcGIS Explorer Desktop? Is there a way to do this 'progmatically' in C# (WPF with ArcGIS runtime ...
1
vote
0answers
70 views

Join field from table to a raster layer

I'm trying to join a field in a table to a raster layer. I'm using the tool 'Join Field'. The table is in a excel sheet, but have been imported to a file geodatabase. The table has an ObjectID field ...
1
vote
1answer
72 views

BIOMOD Error message: argument of length 0

I’m using the package BIOMOD in R to modelling habitat in rodent species. The data formatting works but I'm getting this error message when I run Modelling: ## Conputing the models ## ...
1
vote
0answers
90 views

Creating Raster with values based on function output

I have a function that calculates a price based on the input slope and distance. I want to write the price to a raster as the rastervalue. How do I do that? OpenSource and ArcMap solutions would work. ...
1
vote
3answers
700 views

How to make polygon from cells of a raster?

I have 100 rasters, each raster has the same cell size and extent and i want to make a polygon of each cell. Can anyone help me doing this?
0
votes
1answer
169 views

Can you use a large file directory of jpgs for without georeferencing

I have a large map data set of 256x256 jpg images. The file directory is organized by /map_type/zoom/x/y.jpg. I have 12 zoom levels and each zoom level directory has 2^(2*zoom level) images. I have ...
0
votes
2answers
218 views

Make a “Shaded Area Polygon” from HILLSHADE raster in ArcInfo 9.3

How am I suppose to extract the values ( Value<=100 ) from this HILLSHADE raster, and then make the extracted values as a VECTOR POLYGON (shapefile) ---I'm using ArcGIS 9.3 (ArcInfo with all ...
4
votes
2answers
930 views

GDAL does not ignore NoData value

I am trying to calcualate the statistics of a TIFF. The script should ignore the NoData value, but doesn't. What causes this? import gdal from gdalconst import * # register all of the drivers ...
3
votes
0answers
53 views

arcpy adding time to Raster Mosiac Footprint

I am trying to create a raster mosiac for use in animating data over time. The current workflow is: Create .gdb (arcpy.CreateFileGDB_management) Create Raster Mosaic ...
6
votes
3answers
2k views

Garmin etrex raster maps support

I currently use an excellent set of printed topographic route maps for mountain biking. I would like to scan the maps, georeference them, and upload the maps to a handheld GPS device. Does the etrex ...
3
votes
1answer
176 views

Polygon to Raster is taking longer in script than in arcmap

I have a large dataset that I am working with. Basically I have a table with 900,000 records that I join to a geodatabase feature layer, then convert that to a raster. This process takes a total of ...
2
votes
0answers
376 views

Are there any examples of WCS getcoverage requests done using ajax?

I am looking through openlayers to try to figure out a consistent format for generating views of coverages that can satisfy any wcs server, but mainly I'd like to get geoserver coverages. While I've ...
0
votes
1answer
165 views

ArcGIS 10 rasters/features in ArcGIS 9.3

I am tempted to go back to ArcGIS 9.3 from ArcGIS 10. For what I do, 9.3 is more efficent. Now...I know I cannot open ArcGIS 10 documents (maps, scenes) and layers in 9.3 unless saved as 9.3 file, ...
9
votes
1answer
3k views

Differences between Raster Dataset, Raster Catalog, and Raster Mosaic

I have about 40 scanned, colorful Geology maps that are GeoTiffs. I want to bring them into an Esri FileGeodatabase to lower their size, combine them as one and display them with a mostly transparent ...
4
votes
1answer
580 views

How to sum or even perform more complex mathematical operations (multiply, add a constant, …) two GDAL grids?

I have two grids with same cell size, same starting position (top left) and same grid size. I want to sum the grids and create a sum grid as an result: e.g. grid A + grid B = grid C How can I ...
1
vote
1answer
548 views

How to replace values in rasters in directory 1 based on condition on other rasters in another directory?

Having 10 raster files in one directory and another 10 rasters in another directory and both have the same dimensions. directory 1: files1 <- list.files("C:\\2010", "*.envi", full.names = ...
5
votes
3answers
563 views

Finding outliers with wrong Z values in LIDAR data

I have more than 2000 XYZ (only ground points) .txt files and I have to do Quality Control (QC). Let's say I have file, which I converted to multipoint (or even singlepart feature). I have mean Z ...
4
votes
1answer
240 views

How do I write XML metadata with Python?

Some Python software I have written generates raster files via GDAL. I would like the software to create an XML metadata file for each raster so that I can include details about how the raster was ...
0
votes
0answers
73 views

Four band raster - ColorInterp of the IR band

I have a four band aerial photography raster. The bands contain Red, Green, Blue, and IR data. Using GDALInfo we get something like this currently: Band 1 Block=2933x1 Type=UInt16, ...
2
votes
2answers
442 views

Calculate Percent coverage using another raster, with dif resolution and orientation

I have a 0.5 meter raster that defines presence or absence (cells are either 1 or 0). I have another 5 meter raster, which I created. I would like to calculate a percent coverage of the underlying 0.5 ...
1
vote
1answer
139 views

Scanned Transparent Map Overlay

We have a flat file of 50 Geology maps that have a transparent overlay with faults and drill holes. I have them scanned and georeferenced as TIF images and they will be used in ArcGIS 10.0, 10.1 and ...
3
votes
0answers
106 views

Is there a tool for automated quality assurance for vector data captured on raster data?

I wonder whether is any tool(or script) in ArcGIS or QGIS which allows to make an automated quality assurance for vector data captured on raster data? vector data on binary raster:
0
votes
1answer
166 views

How to get the absolute raster row / column of rastercell when using ArcObject Raster Cursor?

When using the ArcObject RasterCursor (see snippet below), how do I get the absolute row / column of the current pixel value? IRasterCursor rasterCursor = raster.CreateCursorEx(null); do { ...
1
vote
1answer
649 views

How to assign new values to a raster attribute table - by comparing two fields?

I have created a new raster from two raster datasets using combine operation in ArcGIS. The new attribute table has two fields from the input rasters. What I need is, to compare these two fields and ...
3
votes
2answers
623 views

Majority filter (minimum mapping unit) in ArcGIS with larger window size

I want to run the majority filter in ArcGIS with a window size of 4 or 5 i.e. greater than the default 3. Is it possible? Or some other command (or tool) which might help me achieve that? thanks!
1
vote
0answers
46 views

How to Convert Multiple Raster in to NettCDF in Arcmap 10.1?

My name is Paresh Chaudhary and I've worked in the field of Geometics since 2008. I have 30 day by day surface temperature images of MODIS, aqua satellite. Now i want to convert it into a NetCDF ...
3
votes
1answer
237 views

Can ArcGIS handle missing values to create a contour map?

I am trying to create a contour map for a waterbody. It turns out that in several locations there is no data. I just don't want to use the missing values as zero in ArcGIS because it would create ...
1
vote
0answers
103 views

How can I create a multi layer exportable file (.xcf .psd) from multiple raster image in QGIS?

I have many raster file of the same zone but in differents spectral bands. I would like to create an exportable file of a small portion that can handle different layers. So in practice I would like to ...
1
vote
0answers
123 views

Are there limitations with gdal virtual raster option?

I am new at Postgis and I'm groping... I pretend to rasterize some weighty vector layers in Postgis, do some map algebra and reclassification with them and visualize intermediate as well as final ...
2
votes
1answer
89 views

Displaying raster attributes on data driven pages

I have a feature class of 50 properties that are ranked. I have a photo for each property stored in a raster attribute column (in the feature class) called "Picture". I am trying to create a Dynamic ...
5
votes
1answer
942 views

Save Visible WMS layer to file

Is there tool to save currently visible WMS layer to file in QGIS, or some place in QGIS where you can get needed xml to fetch it using gdal ?
2
votes
1answer
183 views

How to reclassify grey scale tiff in qgis

I downloaded a raster image of the sea floor age. The values in band 1 ranges from -32768 to 32767. I need to reclassify it to no. of million of years to make sense of the data. How can I do so? I try ...
3
votes
1answer
582 views

Model builder - Nesting models to extract raster values to points

Hello! Hopefully a quick question. I have a simple model below that iterates through a folder full of rasters, taking each in turn to extract data values based on a single shapefile of Random point ...
0
votes
2answers
1k views

how to convert grid from Saga gis to have raster in Arcgis?

i am new in Saga Gis, i created grid- LS factor (from Rusle equation for erosis) in Saga gis and now i need to "put" it to Arcgis. How can i do this? I tried a lot of possibilities and none of them ...
5
votes
1answer
95 views

Best Practice for maintaining a “Cleanup Floor”

I do not have a GIS background and was hoping that someone could point me in the right direction as to the best procedure / software to do the following. Starting with a current LiDAR survey, I need ...
5
votes
1answer
2k views

How to calculate the flood volume using a LiDAR DEM and a HEC-RAS floodplain polygon

I’ve got a vexing GIS analysis problem which is conceptually fairly straightforward, but in reality more challenging to figure out…. Basically, I need to calculate the VOLUME of floodwater within a ...
2
votes
2answers
152 views

How do I stop null values from being assigned extreme color values?

I have a raster surface that I kriged in Surfer and imported to Grass GIS but when I view it in QGIS, the null values outside of the interpolated surface take an extreme value and wash out the ...
23
votes
2answers
2k views

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'd like to generate a map that highlights the magnitude of positive or negative trends in this ...
2
votes
1answer
106 views

What is No Data Value?

I'm looking at the transparency window of the layer properties of my "Heat map". How does the No Data Value effect a raster layer. I'm assuming an initial setting of -9999 sets it out of the way, so ...
6
votes
1answer
2k views

Best Way to Handle Many Raster Files in QGIS?

I have a project with a large number of raster files, but it is becoming very slow. I wonder which is the best way to handle all this. I'm simply georeferencing these files creating .wld file (geoTiff ...
3
votes
2answers
869 views

How to calculate the area of rasters in QGIS?

I have been working with some rasters and would like to know how to calculate the area occupied by one element of a raster in Qgis.
1
vote
1answer
444 views

What are Bands, Dimensions, and Histograms in QGIS?

First; I can see a band as synonymous with a channel in an image editing program like GIMP, is this correct? If so then bands play the role of color mixing and masking. Are there any other ...
3
votes
1answer
71 views

What defines a Class in the Heat map plugin?

What defines a Class in the Heat map plugin? As in: "Black holes like that are usually caused by raster values exceeding the range of the color ramp. Try adding another class with a higher associated ...
8
votes
1answer
503 views

Calculating distance from points to different class in raster

I am looking for some advice on how to calculate the distance from a point to a different class of a raster. Specifically, I have observations (points) of animal use overlaid on land cover data. For ...
3
votes
1answer
1k views

How to convert jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop ...
3
votes
0answers
142 views

How does Zonal statistics handle pixels that are on the border of the polygon?

I am using the plugin zonal statistics to calculate the sum of the raster cells within polygons. How does this plugin handle pixels that are on the border of the polygon, are those cell values ...
1
vote
1answer
101 views

Problem loading raster to PostGIS using QGIS

I am having trouble loading a raster (.asc) file to PostGIS 2.0.1 using the plugin Database - PostGIS Raster - Load raster to postgis in QGIS 1.8.0 on Win Vista 64 bit. I get the following error ...
1
vote
1answer
222 views

Qgis - Raster clip Problem

I tried to use the Raster (Extration) tool "clipper" and I always get this error log: What is my problem? Fehler bei der Ausführung von Python-Code: Traceback (most recent call last): File ...