ascii-grid - npm Package Compare versions

Comparing version 1.1.0 to 1.2.0

src/calc-ascii-grid-stats.js

+const calcStats = require("calc-stats");
+const parseAsciiGridMeta = require("./parse-ascii-grid-meta");
+const iterAsciiGridPoint = require("./iter-ascii-grid-point");
+
+function calcAsciiGridStats({
+  assume_clean = true,
+  debug_level = 0,
+  data,
+  max_read_length = Infinity,
+  start_of_data_byte,
+  start_column = 0,
+  end_column, // index of last column (using zero-based index)
+  start_row = 0,
+  end_row, // index of last row (using zero-based index)
+  meta,
+  calcHistogram = true,
+  calcMax = true,
+  calcMean = true,
+  calcMedian = true,
+  calcMin = true,
+  calcMode = true,
+  calcModes = true,
+  calcSum = true
+}) {
+  if (!meta) meta = parseAsciiGridMeta({ data, debug: debug_level >= 1, max_read_length });
+  const { nodata_value } = meta;
+  const iterObj = iterAsciiGridPoint({
+    assume_clean,
+    data,
+    start_of_data_byte,
+    start_column,
+    end_column,
+    start_row,
+    end_row,
+    meta
+  });
+  const iterNum = {
+    next: () => {
+      let obj;
+      // iterate until we reach the end or get a valid value
+      while ((obj = iterObj.next())) {
+        const { done, value } = obj;
+        if (done) return { done };
+        const { num } = value;
+        if (num !== nodata_value) return { done, value: num };
+      }
+    }
+  };
+
+  const stats = calcStats(iterNum, {
+    calcHistogram,
+    calcMax,
+    calcMean,
+    calcMedian,
+    calcMin,
+    calcMode,
+    calcModes,
+    calcSum
+  });
+
+  return stats;
+}
+
+module.exports = calcAsciiGridStats;

src/for-each-ascii-grid-point.js

+const iterAsciiGridPoint = require("./iter-ascii-grid-point");
+
+module.exports = ({
+  assume_clean = true,
+  debug_level = 0,
+  data,
+  max_read_length = Infinity,
+  start_of_data_byte,
+  start_column = 0,
+  end_column, // index of last column (using zero-based index)
+  start_row = 0,
+  end_row, // index of last row (using zero-based index)
+  meta,
+  callback
+}) => {
+  if (debug_level >= 1) console.time("[asci-grid/for-each-point] took");
+
+  const iter = iterAsciiGridPoint({
+    assume_clean,
+    debug_level,
+    data,
+    max_read_length,
+    start_of_data_byte,
+    start_column,
+    end_column,
+    start_row,
+    end_row,
+    meta
+  });
+
+  let obj;
+  while (((obj = iter.next()), obj.done === false)) {
+    callback(obj.value);
+  }
+
+  if (debug_level >= 1) console.timeEnd("[asci-grid] parse-ascii-grid-data took");
+};

src/iter-ascii-grid-point.js

+const getByte = require("get-byte");
+const parseAsciiGridMetaData = require("./parse-ascii-grid-meta");
+
+const NEWLINE_CHARCODE = "\n".charCodeAt(0);
+const SPACE_CHARCODE = " ".charCodeAt(0);
+const MINUS_CHARCODE = "-".charCodeAt(0);
+const ZERO_CHARCODE = "0".charCodeAt(0);
+const NINE_CHARCODE = "9".charCodeAt(0);
+const DOT_CHARCODE = ".".charCodeAt(0);
+const NULL_CHARCODE = 0;
+
+/*
+  Notes: .asc files can end with a newline, null byte, or number
+*/
+
+module.exports = ({
+  assume_clean = true,
+  debug_level = 0,
+  data,
+  max_read_length = Infinity,
+  start_of_data_byte,
+  start_column = 0,
+  end_column, // index of last column (using zero-based index)
+  start_row = 0,
+  end_row, // index of last row (using zero-based index)
+  meta,
+  callback
+}) => {
+  if (debug_level >= 1) console.time("[asci-grid/for-each-point] took");
+  let numstr = "";
+
+  if (end_column < start_column) throw new Error("[ascii-grid/for-each-point] end_column must be greater than or equal to start_column");
+  if (end_row < start_row) throw new Error("[ascii-grid/for-each-point] end_row must be greater than or equal to start_row");
+
+  const read_length = Math.min(data.length, max_read_length);
+  if (debug_level >= 1) console.log("[ascii-grid/for-each-point] read_length:", read_length);
+
+  if (!meta) meta = parseAsciiGridMetaData({ data });
+  if (debug_level >= 1) console.log("[ascii-grid/for-each-point] meta:", meta);
+
+  if (!end_row) end_row = meta.nrows - 1;
+  if (debug_level >= 1) console.log("[ascii-grid/for-each-point] end_row:", end_row);
+
+  if (!end_column) end_column = meta.ncols - 1;
+  if (debug_level >= 1) console.log("[ascii-grid/for-each-point] end_column:", end_column);
+
+  let i = start_of_data_byte !== undefined ? start_of_data_byte : meta.last_metadata_byte + 1;
+  if (debug_level >= 1) console.log("[ascii-grid/for-each-point] i:", i);
+
+  // index of current row
+  let r = 0;
+
+  // index of current column
+  let c = 0;
+
+  // previous character
+  let prev;
+
+  return {
+    next: () => {
+      let ret;
+      while (i <= read_length) {
+        // add phantom null byte to end, because of the processing algo
+        const byte = i === read_length ? NULL_CHARCODE : getByte(data, i);
+
+        if (debug_level >= 2) console.log("[ascii-grid/for-each-point] i, byte:", [i, String.fromCharCode(byte)]);
+
+        if (byte === SPACE_CHARCODE || byte === NEWLINE_CHARCODE || byte === NULL_CHARCODE) {
+          if (prev === SPACE_CHARCODE || prev === NEWLINE_CHARCODE || prev === NULL_CHARCODE) {
+            // don't do anything because have reached weird edge case
+            // where file has two white space characters in a row
+            // for example, a new line + space before the start of the next row's data
+            prev = byte;
+            i++;
+            continue;
+          }
+
+          if (numstr !== "" && c >= start_column && c <= end_column) {
+            const num = parseFloat(numstr);
+            if (r >= start_row && r <= end_row) {
+              ret = {
+                value: { c, r, num },
+                done: false
+              };
+            }
+          } else {
+            if (debug_level >= 2) console.log("[ascii-grid/for-each-point] skipping value at [", r, "][", c, "]");
+          }
+
+          numstr = "";
+
+          // reached end of the row
+          if (c == meta.ncols - 1) {
+            r++;
+            c = 0;
+          } else {
+            c++;
+          }
+        } else if (
+          assume_clean ||
+          byte === MINUS_CHARCODE ||
+          byte === ZERO_CHARCODE ||
+          byte === NINE_CHARCODE ||
+          byte === DOT_CHARCODE ||
+          (byte > ZERO_CHARCODE && byte < NINE_CHARCODE)
+        ) {
+          numstr += String.fromCharCode(byte);
+        } else if (debug_level >= 2) {
+          console.error("[ascii-grid/for-each-point]: unknown byte", [byte]);
+        }
+
+        prev = byte;
+        i++;
+        if (ret) return ret;
+      }
+      return {
+        value: undefined,
+        done: true
+      };
+    }
+  };
+};

package.json

 {
   "name": "ascii-grid",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Identify and Read an ARC/INFO ASCII Grid",
@@ -10,3 +10,6 @@ "main": "src/index.js",
     "src/parse-ascii-grid-data.js",
-    "src/parse-ascii-grid-meta.js"
+    "src/parse-ascii-grid-meta.js",
+    "src/calc-ascii-grid-stats.js",
+    "src/for-each-ascii-grid-point.js",
+    "src/iter-ascii-grid-point.js"
   ],
@@ -46,4 +49,5 @@ "scripts": {
   "dependencies": {
+    "calc-stats": "^0.0.2",
     "get-byte": "0.0.0"
   }
 }

README.md

@@ -118,1 +118,48 @@ # ascii-grid: beta
 ```
+
+## Streaming Grid Points
+If you don't want to save a large array of all the grid points,
+but rather iterate over the points with a callback, see below:
+```javascript
+const forEachAsciiGridPoint = require("ascii-grid/for-each-ascii-grid-point");
+
+forEachAsciiGridPoint({
+  data: buffer,
+  callback: ({ c, r, num }) => {
+    console.log("row index is", r);
+    console.log("column index is", c);
+    console.log("value is", num);
+  }
+});
+```
+
+## Calculating Statistics
+You can calculate statistics for the ASCII grid.  Calculations are made by iterating
+over the grid points in a memory-aware way, avoiding loading the whole grid into memory.
+It uses [calc-stats](https://github.com/DanielJDufour/calc-stats) for the calculations.
+```javascript
+const calcAsciiGridStats = require("ascii-grid/calc-ascii-grid-stats");
+
+const stats = calcAsciiGridStats({ data: buffer });
+/*
+  stats is
+{
+    median: 24.926056,
+    min: -275.890015,
+    max: 351.943481,
+    sum: 304535462.0868404,
+    mean: 13.685328213781924,
+    modes: [6.894897],
+    mode: 6.894897,
+    histogram: {
+      "23.1291283": {
+        n: 23.1291283, // the actual value in numerical format
+        ct: 82 // number of times that n appears
+      },
+      .
+      .
+      .
+    }
+  }
+*/
+```

src/index.js

 const isAsciiGrid = require("./is-ascii-grid");
 const parseAsciiGridData = require("./parse-ascii-grid-data");
 const parseAsciiGridMetaData = require("./parse-ascii-grid-meta");
+const calcAsciiGridStats = require("./calc-ascii-grid-stats");
+const iterAsciiGridPoint = require("./iter-ascii-grid-point");
+const forEachAsciiGridPoint = require("./for-each-ascii-grid-point");
 
@@ -8,3 +11,6 @@ module.exports = {
   parseAsciiGridData,
-  parseAsciiGridMetaData
+  parseAsciiGridMetaData,
+  calcAsciiGridStats,
+  iterAsciiGridPoint,
+  forEachAsciiGridPoint
 };

src/parse-ascii-grid-data.js

 const getByte = require("get-byte");
 const parseAsciiGridMetaData = require("./parse-ascii-grid-meta");
+const forEachAsciiGridPoint = require("./for-each-ascii-grid-point");
 
@@ -30,94 +31,43 @@ const NEWLINE_CHARCODE = "\n".charCodeAt(0);
   if (debug_level >= 1) console.time("[asci-grid] parse-ascii-grid-data took");
+
   const result = {};
-  const table = [];
+  const values = [];
   let row = [];
-  let numstr = "";
+  let previous_row_index;
+  let i = 0;
 
-  if (end_column < start_column) throw new Error("[ascii-grid/parse-ascii-grid-data] end_column must be greater than or equal to start_column");
-  if (end_row < start_row) throw new Error("[ascii-grid/parse-ascii-grid-data] end_row must be greater than or equal to start_row");
-
-  const read_length = Math.min(data.length, max_read_length);
-  if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] read_length:", read_length);
-
-  if (!meta) meta = parseAsciiGridMetaData({ data });
-  if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] meta:", meta);
-
-  if (!end_row) end_row = meta.nrows - 1;
-  if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] end_row:", end_row);
-
-  if (!end_column) end_column = meta.ncols - 1;
-  if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] end_column:", end_column);
-
-  let i = start_of_data_byte !== undefined ? start_of_data_byte : meta.last_metadata_byte + 1;
-  if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] i:", i);
-
-  // index of current row
-  let r = 0;
-
-  // index of current column
-  let c = 0;
-
-  // previous character
-  let prev;
-
-  while (i <= read_length) {
-    // add phantom null byte to end, because of the processing algo
-    const byte = i === read_length ? NULL_CHARCODE : getByte(data, i);
-
-    if (debug_level >= 2) console.log("[ascii-grid/parse-ascii-grid-data] i, byte:", [i, String.fromCharCode(byte)]);
-
-    if (byte === SPACE_CHARCODE || byte === NEWLINE_CHARCODE || byte === NULL_CHARCODE) {
-      if (prev === SPACE_CHARCODE || prev === NEWLINE_CHARCODE || prev === NULL_CHARCODE) {
-        // don't do anything because have reached weird edge case
-        // where file has two white space characters in a row
-        // for example, a new line + space before the start of the next row's data
-        prev = byte;
-        i++;
-        continue;
-      }
-
-      if (numstr !== "" && c >= start_column && c <= end_column) {
-        const num = parseFloat(numstr);
-        if (flat) {
-          if (r >= start_row && r <= end_row) {
-            table.push(num);
+  forEachAsciiGridPoint({
+    assume_clean,
+    debug_level,
+    data,
+    max_read_length,
+    start_of_data_byte,
+    start_column,
+    end_column,
+    start_row,
+    end_row,
+    meta,
+    callback: flat
+      ? ({ num }) => values.push(num)
+      : ({ r, num }) => {
+          if (i === 0) {
+            row.push(num);
+          } else if (r !== previous_row_index) {
+            values.push(row);
+            row = [num];
+          } else {
+            row.push(num);
           }
-        } else {
-          row.push(num);
-        }
-      } else {
-        if (debug_level >= 2) console.log("[ascii-grid/parse-ascii-grid-data] skipping value at [", r, "][", c, "]");
-      }
 
-      numstr = "";
-
-      // reached end of the row
-      if (c == meta.ncols - 1) {
-        if (!flat && r >= start_row && r <= end_row) {
-          table.push(row);
+          i++;
+          previous_row_index = r;
         }
-        r++;
-        c = 0;
-        row = [];
-      } else {
-        c++;
-      }
-    } else if (
-      assume_clean ||
-      byte === MINUS_CHARCODE ||
-      byte === ZERO_CHARCODE ||
-      byte === NINE_CHARCODE ||
-      byte === DOT_CHARCODE ||
-      (byte > ZERO_CHARCODE && byte < NINE_CHARCODE)
-    ) {
-      numstr += String.fromCharCode(byte);
-    } else if (debug_level >= 2) {
-      console.error("[ascii-grid/parse-ascii-grid-data]: unknown byte", [byte]);
-    }
+  });
 
-    prev = byte;
-    i++;
+  // make sure don't forget about the last row
+  if (!flat && Array.isArray(row) && row.length > 0) {
+    values.push(row);
   }
 
-  result.values = table;
+  result.values = values;
 
@@ -124,0 +74,0 @@ if (debug_level >= 1) console.log("[ascii-grid/parse-ascii-grid-data] finishing");

New alerts

Major refactor

Supply chain risk

Package has recently undergone a major refactor. It may be unstable or indicate significant internal changes. Use caution when updating to versions that include significant changes.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

23684

31.95%

Number of package files

10

42.86%

Lines of code

344

91.11%

Number of lines in readme file

165

39.83%

Worsened metrics

Dependency count

2

100%

Number of medium supply chain risk alerts

1

Infinity%

Dependency changes

• + Added

  calc-stats@^0.0.2

• + Added

  calc-stats@0.0.2
  (transitive)

• + Added

  faster-median@0.2.1
  (transitive)