Use the `raster` tag for questions about raster datasets. A "grid" is a regular partition of a spatial domain into congruent nonoverlapping pieces or a set of lines forming a grid-like pattern (aka "graticule").

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0
votes
2answers
628 views

How can I generate a fishnet grid and a matrix of percentage of overlapping in R?

I'm trying use R for create a fishnet grid like in arcGIS with many cells of same size. In the arcGIS 9.3 we have the option of create a polygon with many small square polygons (eg. 1 x 1 degree of ...
0
votes
3answers
649 views

How to generate a shapefile with UTM Grid precision level 100 m [duplicate]

Does anybody know, if I can download from somewhere UTM Grid for zones 33 to 35 and U belt (for Poland) in shpfile or different format I can convert to shp. I need precision level 100 m. Is it ...
3
votes
1answer
145 views

draw lines with an angle inside a rectangle in python

I am trying to make a plugin for Qgis with python. I have the four corner coordinates for a rectangle. I want to give the user the inputs, line space and angle (0 -180 degrees). With these inputs, I ...
7
votes
3answers
859 views

Create a square grid polygon shapefile with python

i have the following coordinates minx,maxx,miny,maxy = 448262.080078, 450360.750122, 6262492.020081, 6262938.950073 i wish to create a square grid of size 1 m using python. import math ...
1
vote
1answer
246 views

How to divide a certain country on a map into grids?

I want to divide a certain country into grids 1,2,3,..., which are divided equally - in other words, have the same width and length. Then, I want to know into which grid a point coordinate will fall ...
3
votes
1answer
256 views

Find which grid cells contain a point

I have a dataframe with x,y coordinates. I've sampled 10 x,y coordinates from my dataframe: y <-c(24.637032,21.569813,21.687,19.677183,24.72438,21.433136,24.637032,22.21065,21.443762,25.273882) x ...
2
votes
1answer
131 views

filter / generalize elevation points on the basis of some conditions

I wanted to generalize many elevation points in a rectangular area (about 700 square km). I need to take about 3 points for square km. These points must satisfy some conditions: One of these ...
2
votes
4answers
1k views

ArcInfo Grid ASCII to ESRI Shapefile conversion

I have an ArcGIS grid ascii file (Ramankutty Cropland at 5 minute resolution) that begins as follows: ncols 4320 nrows 2160 xllcorner -180 yllcorner -90 cellsize ...
5
votes
1answer
245 views

Help with grid creation in QGIS

I have 235 raster tile 20km x 20km. I need to create a grid to overlay across them...ie the grid itself will be 20km x 20km, with the lines of the grid on the boundaries of the tiles. I am assuming ...
2
votes
1answer
184 views

How to flip X and Y coordinates of a grid by GDAL

I have a grid, which has flipped X and Y coordinates (X is represented by Y values and Y is represented by X values). This results in grid being positioned in completely wrong place. How can I flip ...
1
vote
1answer
639 views

How to draw grid cells in QGIS?

I have one ASCII text file with eight columns. The first four provide the x-coordinates (e.g. longitude) of the four corners of a grid cell, while the last four provide the y-coordinates (e.g. ...
9
votes
2answers
1k views

Aggregating points to grid using R

I have a question with regard to spatial aggregation in R. What I am trying to do is aggregate a point dataset to a grid. I am unsure however how to do this as I have little experience with this sort ...
2
votes
0answers
127 views

Plot the Shortest Paths in a Grid without any clash at a point of time

The efficient algorithm needs to be done and proved for the best solution for the given problem: User inputs: (#) Size of the NxN Grid. (N); (#) No. of Paths: Z; (#) Source and Destination ...
5
votes
1answer
447 views

Converting polygon values to a vector grid using PostGIS

What is the best way of converting a value from irregularly shaped poylgons to a polygon grid using PostGIS? I have a set of polygons that look like this: and I would like to overlay a grid on ...
4
votes
1answer
126 views

How do I split a vector layer into separate grid layers?

I need to split a vector layer into 1km x 1km squares so I can carry out some calculations for these individual areas. Is there a feature to do this?
2
votes
1answer
744 views

UTM Grid as a Layer with Leaflet

How can I display a UTM Grid as a layer with Leaflet? Search a way to embed a OpenStreetMap map with Leaflet in a website. Particularity. I want to display a UTM Grid as a Layer. In addition, lower ...
2
votes
2answers
306 views

gridlines are on top of some text boxes but below others, how do I make it so that the text boxes are above the gridlines in all cases

I am working with a map and instead of using the labels feature I chose to use text boxes because the labels were not where I wanted them to be. I set up all the text boxes and then added gridlines ...
-1
votes
1answer
539 views

Exporting Grid from R to use it in ArcGIS

i want to export a grid from R into format readable by ArcGIS. how can i do so? jones
1
vote
2answers
443 views

Arcpy (10.0) and centroids/points shapefile

I'm trying to create a point shapefile from a grid index polygon shapefile I created using arcpy. I know this is simple, but could anyone give a few pointers out there. Here is what I've done now: but ...
1
vote
2answers
90 views

Distribute gridded data to corresponding subbasin boundaries

I have one ArcGIS shapefile of my river basin consisting of many subbasin. Another shapefile showing the location of gridded points over the whole basin (Its latitude and longitude are used as file ...
5
votes
1answer
524 views

How to emulate a specific vector grid in QGIS?

I would like to analyze data included in a pdf file. The file contains information on characteristics of 16km grid cells for a specific study area. The file also includes a map displaying the grid. I ...
0
votes
0answers
95 views

How do I determine programmatically what values to add to the proj4js constructor for a CRS or SRS such that I can iteratively render proper overlays

I think this is primarily a GIS based question as far as for example: var crs = L.CRS.proj4js('EPSG:2154', '+proj=lcc +lat_1=49 +lat_2=44 +lat_0=46.5 +lon_0=3 +x_0=700000 ...
5
votes
1answer
130 views

How to convert PostGis Table (Grid data) to Continuous field using Qgis?

I'd like to transform my Gridded Layer (generated form a PostGIS table of points) to a continuous and colored layer. How could I do this with Qgis or any other program? Many thanks and best regards, ...
2
votes
3answers
496 views

Looking for a fine U.S. Latitude and Longitude grid (0.25, 0.5 degree)

There is a global latitude and longitude grid data available at 1 degree resolution and higher (http://www.arcgis.com/home/item.html?id=f11bcdc5d484400fa926dcce68de3df7). Is anyone aware of a finer ...
6
votes
3answers
934 views

Find a proper path between two nodes in a grid

This question is about finding a proper path (route) between two nodes (P,Q) in a grid (i.e., graph, network, ...). In our concept, we define a path proper (nice) if it is the most similar* to the ...
3
votes
1answer
208 views

Polyline “breakage” calculation in MapInfo?

I am a novice MapInfo user, with a basic to moderate knowledge of queries and SQL. My work entails doing risk assessments for shipping traffic based on AIS-tracks (radio-based vessel information ...
1
vote
0answers
266 views

In ArcGis 10, spatial join of a hot street value to a fishnet cell is counting multiple values for same street segment

So, I am working on a fishnet, so that we can attribute multiple values to points within different cells (i.e., ranking light poles as optimum for traffic cameras based on the number of speeding ...
4
votes
1answer
720 views

How to create a 500m Regular Grid for KML input area?

I am hoping to create a point grid over the city of Edmonton. My workflow is: Import a KML of Edmonton neighborhoods from here Save the layer as a SHP Delete the layer and load the SHP Define the ...
2
votes
1answer
1k views

Convert X Y Pixels to Easting Northing

Hopefully someone can help. I'm trying to find out what the formula would be to convert the X, Y of an image to the Easting and Northing coordinates. I've downloaded some of the raster maps from OS ...
0
votes
2answers
269 views

QGIS regular points around each polygon in a layer (vs ALL polygons)

I have a number of buffered points (some where polygons intersect & are dissolved. I'd like to create regular spaced points grid around EACH polygon -- not ALL polygons. When I do Vector -> ...
6
votes
2answers
4k views

Create a polygon layer from point data

I'm currently using QGIS 1.8.0 I would like to create a polygon layer from a point dataset, where the size of the polygons relates to the resolution of the grid reference. The ultimate aim would be ...
2
votes
1answer
159 views

How extract data from a SNODAS file

I'm trying to extract data from a raster file from "Snow Data Assimilation System (SNODAS)" and convert it to a MMQGIS (plugin) grid layer (Hexagon) with QGIS. This raster file stores the snow depth ...
0
votes
0answers
933 views

Lat/long grid in QGIS using WGS84 projected layers [duplicate]

I'm using QGIS to project some shapes that are in WGS84 coordinate system. I want to add a grid to the map in the map composer but when I try to do it the degrees don't show up. I have tried to do ...
2
votes
1answer
471 views

How to export vector features to grid using proxy and WFS protocol?

I am trying to export vector features (current view) as a grid, something like: http://workshops.opengeo.org/geoext/wfs/grid.html so far layer features are not being retrieved.. I got empty grid in ...
1
vote
1answer
552 views

How to convert a polygon to a grid of polygons using QGIS?

For example, the city of Rotterdam represented as a hexagonal grid.
3
votes
1answer
74 views

How to modify height model values outside of road network

I have a height model of a quite big area saved in Esri ASCII grid files and a road network of this same area in a shapefile. I'd like to convert every height model value outside the road network to ...
1
vote
1answer
241 views

Grid labels in ArcGIS, overlapping issues

I do have 3 grids made by Grids menu in data frame properties. I do need them to display in certain layout and also to behave accordingly to couple of rules (overlapping issues), so I can automate my ...
0
votes
1answer
113 views

Why are grid and scalebar measures 1mm too long in a 1:10000 print?

I used qgis 1.8 to compose a map from the WMS-service of the Belgian NGI. I added a scalebar and grid to it. When I measure it by hand, the distance between the longitudelines is 101mm instead of ...
0
votes
0answers
133 views

SAGA grid VRT, file how to apply a LUT?

I've created a heap of saga grid files for some hydro survey work. I'm looking at a way to read these into a mapguide raster/grid layer, I'm able to load up the grids using a vrt file, I can't figure ...
-1
votes
1answer
322 views

how to make grid cells by point data

I have a csv data. the X, and Y columns show bottom left corner of each grid. It is supposed to show as grid square, but it shows points. what is the problem? and is there any way I can make cell ...
3
votes
0answers
109 views

How to view Esri GRID format file in wxpython file browse window? [closed]

I'm trying to browse for all kinds of vector and raster data using a filebrowsebutton. The problem is I don't know how to let the browse window see the Esri GRID files (which contains a folder and a ...
11
votes
4answers
1k views

How can I generate irregular grid containing minimum n points?

Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain ...
6
votes
1answer
2k views

Grid and Graticule in QGIS Print Composer

Is there any other option to display DMS grid and graticule in QGIS Print Composer, since there is no plugins available yet?
3
votes
2answers
408 views

How to display DMS in QGIS print composer?

Can we display degrees, minutes, seconds in QGIS Print Composer window instead of decimal degrees? Is there any plugins available for that? Thank you very much.
2
votes
1answer
900 views

How to create a grid constrained within a polygon in QGIS?

In QGIS I have created an irregularly shaped polygon. I can create a grid based on the maximum extents of the polygon via Vector>Research Tools>Vector Grid. However, what if I need the grid to ...
4
votes
1answer
422 views

How to specify coordinate reference system (CRS) for scalebar that is different to project CRS?

Is it possible to specify a coordinate reference system (CRS) for the scalebar that is different to the project CRS? For example, my project CRS uses geographic coordinates (lat/long), the reason ...
1
vote
2answers
539 views

How to create a valid global polygon grid in PostGIS?

I want to create a grid spawning the whole globe. The grid is used to measure a density value by counting the number of certain spatial objects in each grid cell. To create the grid, I have created ...
8
votes
3answers
1k views

Creating regularly spaced, defined # of points within polygon in QGIS

I used the research tool "Regular Points" to produce a certain number of points within a polygon, but it forms a rectangular grid of points rather than only within the shape of the polygon. Since I ...
5
votes
2answers
382 views

Optimum grid/pixel size for interpolating rainfall and temperature

I have a set monthly rainfall and temperature data within an approximately 100 x 100 km study area. The sampling points are unevenly distributed within the study area. Based on a paper by Janis et. ...
0
votes
2answers
288 views

How to implement a spatial query on polygon data for a specific point?

I have vector data fed into a database which returns a report at province level upon querying. This is implemented in a web tool. I want to add an extra functionality at point level, where I can ...